Regex to extract text from a string - javascript

Given the following string:
const myString = "This is my comment content. [~firstName.lastName]";
What is a javascript regex to extract the "firstName" and "lastName"?
What is a javascript regex to extract the content minus the "[~firstName.lastName]"?
I'm rubbish with Regex.


const myString = "This is my comment content. [~firstName.lastName]";
const first = myString.match(/.*\~(.*)\./)[1]
const last = myString.match(/.*\.(.*)]/)[1]
const both = myString.match(/.*\~(.*)\]/)[1]
console.log(first)
console.log(last)
console.log(both)
Here's a good website for regex help


You can try this-
let myString = "This is my comment content. [~firstName.lastName] and the original name is [~John.Doe]";
const regex = /\[~([^\]]+)\.([^\]]+)\]/g;
let match = regex.exec(myString);
const names = [];
while(match !== null) {
names.push({firstName: match[1], lastName: match[2]});
match = regex.exec(myString);
}
// Remove the pattern from the original string.
myString = myString.replace(regex, '');
console.log(names, myString);
This code will find all the matches found for the pattern.


You could target each name separately. match will return the complete match as the first element of the array, and the groupings specified by the ( and ) in the regex as the subsequent elements.
const str = 'This is my comment content. [~firstName.lastName]';
const regex = /\[~(.+)\.(.+)\]/;
console.log(str.match(regex));
Or you could target just the characters within the brackets and then split on the ..
const str = 'This is my comment content. [~firstName.lastName]';
const regex = /\[~(.+)\]/;
console.log(str.match(regex)[1].split('.'));

Related

Remove string from string using regex and return part of removed

I am trying to extract a component name from a string so I can parse the rest with JSON and also return the component name.
Let's say I have a string as follows:
namespace/Slider {"showCaptions":true,"circular":false,"autoPlay":true,"showItemNavigators":true,"showItemNavigatorsOnHover":true,"showIndicators":false,"indicatorsPosition":"bottom","showThumbnails":true,"numVisible":10,"numVisible1536":8,"numVisible1280":6,"numVisible1024":4,"numVisible768":3,"numVisible640":2,"changeItemOnIndicatorHover":false,"images":[{"id":1701,"url":"http://localhost:10019/wp-content/uploads/2022/12/horse.jpeg","alt":"horse alt","caption":"Name some name"},{"id":1699,"url":"http://localhost:10019/wp-content/uploads/2022/12/GPJNews_Mongolia_KK_RidingChild_076_web-920x613-1.jpeg","alt":"","caption":"Name GP"},{"id":1238,"url":"http://localhost:10019/wp-content/uploads/2022/08/test-scaled.jpeg","alt":"","caption":""},{"id":458,"url":"http://localhost:10019/wp-content/uploads/2022/09/news-scaled-1.jpeg","alt":"","caption":"Paswan a mother who..."}]}
I want to remove the "namespace/Slider" part from the string and return the rest so I can JSON.parse it and also want to return "Slider" so the part after namespace as a variable.
EDIT: This is how I was doing it before and it worked until I had a ( in any of the fields eg: "caption":"(Name GP"
const str = `namespace/Slider {"showCaptions":true,"circular":false,"autoPlay":true,"showItemNavigators":true,"showItemNavigatorsOnHover":true,"showIndicators":false,"indicatorsPosition":"bottom","showThumbnails":true,"numVisible":10,"numVisible1536":8,"numVisible1280":6,"numVisible1024":4,"numVisible768":3,"numVisible640":2,"changeItemOnIndicatorHover":false,"images":[{"id":1701,"url":"http://localhost:10019/wp-content/uploads/2022/12/horse.jpeg","alt":"horse alt","caption":"Name some name"},{"id":1699,"url":"http://localhost:10019/wp-content/uploads/2022/12/GPJNews_Mongolia_KK_RidingChild_076_web-920x613-1.jpeg","alt":"","caption":"Name GP"},{"id":1238,"url":"http://localhost:10019/wp-content/uploads/2022/08/test-scaled.jpeg","alt":"","caption":""},{"id":458,"url":"http://localhost:10019/wp-content/uploads/2022/09/news-scaled-1.jpeg","alt":"","caption":"Paswan a mother who..."}]}`;
const component = str
.replace(/\{([^()]|())*\}/gi, '')
.trim()
.split('/')[1];
const obj = str.match(/\{([^()]|())*\}/gi)[0]
console.log(component, obj);

Take the substring starting from the first { character.
let str = 'namespace/Slider {"showCaptions":true,"circular":false,"autoPlay":true,"showItemNavigators":true,"showItemNavigatorsOnHover":true,"showIndicators":false,"indicatorsPosition":"bottom","showThumbnails":true,"numVisible":10,"numVisible1536":8,"numVisible1280":6,"numVisible1024":4,"numVisible768":3,"numVisible640":2,"changeItemOnIndicatorHover":false,"images":[{"id":1701,"url":"http://localhost:10019/wp-content/uploads/2022/12/horse.jpeg","alt":"horse alt","caption":"Name some name"},{"id":1699,"url":"http://localhost:10019/wp-content/uploads/2022/12/GPJNews_Mongolia_KK_RidingChild_076_web-920x613-1.jpeg","alt":"","caption":"Name GP"},{"id":1238,"url":"http://localhost:10019/wp-content/uploads/2022/08/test-scaled.jpeg","alt":"","caption":""},{"id":458,"url":"http://localhost:10019/wp-content/uploads/2022/09/news-scaled-1.jpeg","alt":"","caption":"Paswan a mother who..."}]}';
let idx = str.indexOf('{');
console.log(str.slice(str.indexOf('/') + 1, idx));
console.log(JSON.parse(str.slice(idx)));

This example uses replace(), sub-expressions (sub-expression) and back-references $number:
let str = 'namespace/Slider {"showCaptions":true,"circular":false,"autoPlay":true,"showItemNavigators":true,"showItemNavigatorsOnHover":true,"showIndicators":false,"indicatorsPosition":"bottom","showThumbnails":true,"numVisible":10,"numVisible1536":8,"numVisible1280":6,"numVisible1024":4,"numVisible768":3,"numVisible640":2,"changeItemOnIndicatorHover":false,"images":[{"id":1701,"url":"http://localhost:10019/wp-content/uploads/2022/12/horse.jpeg","alt":"horse alt","caption":"Name some name"},{"id":1699,"url":"http://localhost:10019/wp-content/uploads/2022/12/GPJNews_Mongolia_KK_RidingChild_076_web-920x613-1.jpeg","alt":"","caption":"Name GP"},{"id":1238,"url":"http://localhost:10019/wp-content/uploads/2022/08/test-scaled.jpeg","alt":"","caption":""},{"id":458,"url":"http://localhost:10019/wp-content/uploads/2022/09/news-scaled-1.jpeg","alt":"","caption":"Paswan a mother who..."}]}';
let name = str.replace(/(namespace)\/(\w+)\s+(\{.+\})/, "$2") // Slider
let json = str.replace(/(namespace)\/(\w+)\s+(\{.+\})/, "$3") // {...}
The same example example uses match() and sub-expressions (sub-expression):
let str = 'namespace/Slider {"showCaptions":true,"circular":false,"autoPlay":true,"showItemNavigators":true,"showItemNavigatorsOnHover":true,"showIndicators":false,"indicatorsPosition":"bottom","showThumbnails":true,"numVisible":10,"numVisible1536":8,"numVisible1280":6,"numVisible1024":4,"numVisible768":3,"numVisible640":2,"changeItemOnIndicatorHover":false,"images":[{"id":1701,"url":"http://localhost:10019/wp-content/uploads/2022/12/horse.jpeg","alt":"horse alt","caption":"Name some name"},{"id":1699,"url":"http://localhost:10019/wp-content/uploads/2022/12/GPJNews_Mongolia_KK_RidingChild_076_web-920x613-1.jpeg","alt":"","caption":"Name GP"},{"id":1238,"url":"http://localhost:10019/wp-content/uploads/2022/08/test-scaled.jpeg","alt":"","caption":""},{"id":458,"url":"http://localhost:10019/wp-content/uploads/2022/09/news-scaled-1.jpeg","alt":"","caption":"Paswan a mother who..."}]}';
let matches = str.match(/(namespace)\/(\w+)\s+(\{.+\})/)
let name = matches[2] // Slider
let json = matches[3] // {...}

Using regex match and destructuring to get the relevant parts
const str = `namespace/Slider {"showCaptions":true,"circular":false,"autoPlay":true,"showItemNavigators":true,"showItemNavigatorsOnHover":true,"showIndicators":false,"indicatorsPosition":"bottom","showThumbnails":true,"numVisible":10,"numVisible1536":8,"numVisible1280":6,"numVisible1024":4,"numVisible768":3,"numVisible640":2,"changeItemOnIndicatorHover":false,"images":[{"id":1701,"url":"http://localhost:10019/wp-content/uploads/2022/12/horse.jpeg","alt":"horse alt","caption":"Name some name"},{"id":1699,"url":"http://localhost:10019/wp-content/uploads/2022/12/GPJNews_Mongolia_KK_RidingChild_076_web-920x613-1.jpeg","alt":"","caption":"Name GP"},{"id":1238,"url":"http://localhost:10019/wp-content/uploads/2022/08/test-scaled.jpeg","alt":"","caption":""},{"id":458,"url":"http://localhost:10019/wp-content/uploads/2022/09/news-scaled-1.jpeg","alt":"","caption":"Paswan a mother who..."}]}`
const [_,namespace,jsonString] = str.match(/^\w+\/(.*?) (.*)/);
console.log(namespace,JSON.parse(jsonString));
Explanation
^\w+ // any alpha string from start
\/ // forward slash
(^.*?) // group from slash to whatever comes next in this case the space
// space
(.*) // group from after space to end

Regex match for string between / and .jsp

If I do regex match for
str = "/mypage/account/info.jsp"
str.match('\/.*\.jsp')
I get entire string but I want to grab only "info"
How can I accomplish using only regex?

First, you can get the text after the last /
/[^/]*$/
and then get the desired result using split
const str = "/mypage/account/info.jsp";
const match = str.match(/[^/]*$/);
const result = match && match[0].split(".")[0];
console.log(result);
only regex
const str = "/mypage/account/info.jsp";
const match = str.match(/[^/]+(?=\.jsp$)/);
console.log(match[0]);

Replace substring with its exact length of another character

I am trying to replace a substring within a string with an exact number of other characters.
Example:
Input: Hello There, General Kenobie!
Output: xxxxx There, xxxxxxx Kenobie!
I can get this to work if I replace it with a preset string:
const text = "'Hello' There, 'General' Kenobie!"
const pattern = /(?:'([^']*)')|(?:"([^"]*)")/g;
console.log(text.replace(pattern, "xxx"));
Output: xxx There, xxx Kenobie!
What am I missing wrapping my head around.
Thanks!

You are using a hard-coded string of 'xxx' as your replacement string. So, that's what you are seeing... the string(s) replaced with 'xxx'.
The .replace() method actually supports a function as the replacement, instead of a string, so that's what you need here.
Docs: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replace#Specifying_a_function_as_a_parameter
const text = "'Hello' There, 'General' Kenobie!"
const pattern = /(?:'([^']*)')|(?:"([^"]*)")/g;
const newText = text.replace(pattern, (str, m) => 'x'.repeat(m.length));
console.log(newText);

You can always loop through the matches and replace each separately.
let text = "'Hello' There, 'General' Kenobie!"
const pattern = /(?:'([^']*)')|(?:"([^"]*)")/g;
let array1;
while ((array1 = pattern.exec(text)) !== null) {
wrap = array1[0][0];
text = text.replace(array1[0],wrap + "x".repeat(array1[0].length-2) + wrap);
}
console.log(text)

Regex to remove all "" and []

I have a string like this:
const myString = "["dupa", "dupa", "dupa"]";
how to use regex in JS/TS to remove all characters " and [ and ]?
i need only dupa, dupa, dupa
thanks for any help

It will return you string with other removed from it and with your double quoted there is problem with it. So use single quote.
const myString = '["dupa", "dupa", "dupa"]';
const a = myString.replace(/[\[\]']+/g, '').replace(/"/g, '');
console.log(a);
You will get "dupa, dupa, dupa"
Or you can go with :
const myString = '["dupa", "dupa", "dupa"]';
const a = JSON.parse(myString);
console.log(a.join(", "))

Regex to replace colon in JS

I have the following string:
let str = '/user/:username/'
I want to extract replace username with harry with colon removed.
I tried the following:
const regex = /[^:]+(?=:)/g
str.replace(regex, x => console.log(x))

Try: /:\w+/
let str = '/user/:username/'
str.replace(/:\w+/, "harry")
// => "/user/harry/"

let str = '/user/:username/';
let html = str.replace(":username", "harry");
console.log(html);

var str = '/user/:username/';
var newstr = str.replace(/:username/i, "harry");
print(newstr);
hi pal, is this what you are looking for? i found it at https://developer.mozilla.org/de/docs/Web/JavaScript/Reference/Global_Objects/String/replace

you can use like that :
let str = '/user/:username/';
str.replace(':username','harry')
// o/p => /user/harry/"

In your regex [^:]+(?=:) you are matching 1+ times not a colon and assert that at the end there should be a colon resulting in a match for /user/
If you want to use the negated character class you could match a colon and then not a forward slash:
:[^\/]+
const str = `/user/:username/`;
const result = str.replace(/:[^\/]+/, "harry");
console.log(result);

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