Anyone have a regex in javascript for converting:
someCamelCase into some-file-case
or
SomeCamelCase into some-file-case
??
If so, that would be very helpful.
Thanks.
You can make a simple regexp to capture a lowercase letter contiguous to an uppercase one, insert a dash between both and make the result all lowercase.
For example:
function fileCase(str) {
return str.replace(/([a-z])([A-Z])/g, "$1-$2").toLowerCase();
}
fileCase('SomeCamelCase'); // "some-camel-case"
fileCase('someCamelCase'); // "some-camel-case"
Here. try this one.
"SomeCamelCase".replace(/[A-Z]/g, function(m){return '_' + m.toLowerCase();});
or as a function
function camelToHiphen(str){
return str.replace(/[A-Z]/g, function(m){return '_' + m.toLowerCase();});
}
Camel Case <=> Hyphen Case Conversion Methods:
disclaimer : I do not condone
clobbering the String prototype in the
way that I have below.
This is a prototype method on string for doing camelCase to hyphen-case that will account for uppercase beginning characters.
String.prototype.camelToHyphen = function() {
return this.replace(/((?!^)[A-Z])/g, '-$1').toLowerCase();
};
This solution was brought on by my search for the exact opposite.
String.prototype.hyphenToCamel = function() {
return (/-[a-z]/g.test(this)) ? this.match(/-[a-z]/g).map(function(m, n){
return m.replace(n, n.toUpperCase()[1]);
}, this) : this.slice(0);
};
I figure these are common enough issues but I could not find anything immediately that summed them up in this way.
Related
As a follow up to this question (not by me), I need to replace leading numbers of an id with \\3n (where n is the number we're replacing).
Some examples:
"1foo" -> "\\31foo"
"1foo1" -> "\\31foo1"
"12foo" -> "\\31\\32foo"
"12fo3o4" -> "\\31\\32fo3o4"
"foo123" -> "foo123"
Below is a solution that replaces every instance of the number, but I don't know enough regex to make it stop once it hits a non-number.
function magic (str) {
return str.replace(/([0-9])/g, "\\3$1");
}
... Or is regex a bad way to go? I guess it would be easy enough to do it, just looping over each character of the string manually.
Here is a way to achieve what you need using a reverse string + look-ahead approach:
function revStr(str) {
return str.split('').reverse().join('');
}
var s = "12fo3o4";
document.write(revStr(revStr(s).replace(/\d(?=\d*$)/g, function (m) {
return m + "3\\\\";
}))
);
The regex is matching a number that can be followed by 0 or more numbers only until the end (which is actually start) of a reversed string (with \d(?=\d*$)). The callback allows to manipulate the match (we just add reversed \\ and 3. Then, we just reverse the result.
Just use two steps: first find the prefix, then operate on its characters:
s.replace(/^\d+/, function (m) {
return [].map.call(m, function (c) {
return '\\3' + c;
}).join('');
});
No need to emulate any features.
Here is how I would have done it:
function replace(str) {
var re = /^([\d]*)/;
var match = str.match(re)[0];
var replaced = match.replace(/([\d])/g, "\\3$1");
str = str.replace(match, replaced);
return str;
}
document.write(replace("12fo3o4"));
Don't get me wrong: the other answers are fine! My focus was more on readability.
How can I convert PascalCase string into underscore_case/snake_case string? I need to convert dots into underscores as well.
eg. convert
TypeOfData.AlphaBeta
into
type_of_data_alpha_beta
You could try the below steps.
Capture all the uppercase letters and also match the preceding optional dot character.
Then convert the captured uppercase letters to lowercase and then return back to replace function with an _ as preceding character. This will be achieved by using anonymous function in the replacement part.
This would replace the starting uppercase letter to _ + lowercase_letter.
Finally removing the starting underscore will give you the desired output.
var s = 'TypeOfData.AlphaBeta';
console.log(s.replace(/(?:^|\.?)([A-Z])/g, function (x,y){return "_" + y.toLowerCase()}).replace(/^_/, ""));
OR
var s = 'TypeOfData.AlphaBeta';
alert(s.replace(/\.?([A-Z])/g, function (x,y){return "_" + y.toLowerCase()}).replace(/^_/, ""));
any way to stop it for when a whole word is in uppercase. eg. MotorRPM into motor_rpm instead of motor_r_p_m? or BatteryAAA into battery_aaa instead of battery_a_a_a?
var s = 'MotorRMP';
alert(s.replace(/\.?([A-Z]+)/g, function (x,y){return "_" + y.toLowerCase()}).replace(/^_/, ""));
str.split(/\.?(?=[A-Z])/).join('_').toLowerCase();
u're welcome
var s1 = 'someTextHere';
var s2 = 'SomeTextHere';
var s3 = 'TypeOfData.AlphaBeta';
var o1 = s1.split(/\.?(?=[A-Z])/).join('_').toLowerCase();
var o2 = s2.split(/\.?(?=[A-Z])/).join('_').toLowerCase();
var o3 = s3.split(/\.?(?=[A-Z])/).join('_').toLowerCase();
console.log(o1);
console.log(o2);
console.log(o3);
Alternatively using lodash:
lodash.snakeCase(str);
Example:
_.snakeCase('TypeOfData.AlphaBeta');
// ➜ 'type_of_data_alpha_beta'
Lodash is a fine library to give shortcut to many everyday js tasks.There are many other similar string manipulation functions such as camelCase, kebabCase etc.
This solution solves the non-trailing acronym issue with the solutions above
I ported the code in 1175208 from Python to JavaScript.
Javascript Code
function camelToSnakeCase(text) {
return text.replace(/(.)([A-Z][a-z]+)/, '$1_$2').replace(/([a-z0-9])([A-Z])/, '$1_$2').toLowerCase()
}
Working Examples:
camelToSnakeCase('thisISDifficult') -> this_is_difficult
camelToSnakeCase('thisISNT') -> this_isnt
camelToSnakeCase('somethingEasyLikeThis') -> something_easy_like_this
"alphaBetaGama".replace(/([A-Z])/g, "_$1").toLowerCase() // alpha_beta_gamma
Problem - Need to convert a camel-case string ( such as a property name ) into underscore style to meet interface requirements or for meta-programming.
Explanation
This line uses a feature of regular expressions where it can return a matched result ( first pair of () is $1, second is $2, etc ).
Each match in the string is converted to have an underscore ahead of it with _$1 string provided. At that point the string looks like alpha_Beta_Gamma.
To correct the capitalization, the entire string is converted toLowerCase().
Since toLowerCase is a fairly expensive operation, its best not to put it in the looping handler for each match-case, and run it once on the entire string.
After toLowerCase it the resulting string is alpha_beta_gamma ( in this example )
This will get you pretty far: https://github.com/domchristie/humps
You will probably have to use regex replace to replace the "." with an underscore.
I found this but I edited it so suit your question.
const camelToSnakeCase = str => str.replace(/[A-Z]/g, letter => `_${letter.toLowerCase()}`).replace(/^_/,'')
Good examples for js:
Snake Case
Kebab Case
Camel Case
Pascal Case
have here
function toCamelCase(s) {
// remove all characters that should not be in a variable name
// as well underscores an numbers from the beginning of the string
s = s.replace(/([^a-zA-Z0-9_\- ])|^[_0-9]+/g, "").trim().toLowerCase();
// uppercase letters preceeded by a hyphen or a space
s = s.replace(/([ -]+)([a-zA-Z0-9])/g, function(a,b,c) {
return c.toUpperCase();
});
// uppercase letters following numbers
s = s.replace(/([0-9]+)([a-zA-Z])/g, function(a,b,c) {
return b + c.toUpperCase();
});
return s;
}
Try this function, hope it helps.
"TestString".replace(/[A-Z]/g, val => "_" + val.toLowerCase()).replace(/^_/,"")
replaces all uppercase with an underscore and lowercase, then removes the leading underscore.
A Non-Regex Answer that converts PascalCase to snake_case
Note: I understand there are tons of good answers which solve this question elegantly. I was recently working on something similar to this where I chose not to use regex. So I felt to answer a non-regex solution to this.
const toSnakeCase = (str) => {
return str.slice(0,1).toLowerCase() + str.split('').slice(1).map((char) => {
if (char == char.toUpperCase()) return '_' + char.toLowerCase();
else return char;
}).join('');
}
Eg.
inputString = "ILoveJavascript" passed onto toSnakeCase()
would become "i_love_javascript"
I'm trying to do something that would be similar to turning a url slug-like variable into text that could be used for a title.
So, I have a variable for example that is like this:
var thisID = 'athlete-profile';
function myFunc(thisID) {
// i need to use thisID as the id and href in a loop that generates a string of <li><a>'s\
function makeTitle(thisID) {
// convert thisID to text so for this example it would return 'Athlete Profile'
return 'Athlete Profile';
}
for () {
var str = '<li id="'+thisID+'">'+makeTitle(thisID)+'';
}
// make sense?
}
I'd like to not use a regex to do this if possible somehow, but I don't think there's a way to do it without one. So any one who knows how to do this type of thing let me know, it would be a great help.
Thanks
I would advise you to use regular expression. But if you really don't want to use regular expressions, the solution below would work for simple cases. Feel free to modify it as you like it.
function makeTitle(slug) {
var words = slug.split('-');
for (var i = 0; i < words.length; i++) {
var word = words[i];
words[i] = word.charAt(0).toUpperCase() + word.slice(1);
}
return words.join(' ');
}
console.log(
makeTitle("athlete-profile")
)
function titleize(slug) {
var words = slug.split("-");
return words.map(function(word) {
return word.charAt(0).toUpperCase() + word.substring(1).toLowerCase();
}).join(' ');
}
console.log(titleize("athlete-profile"))
It works pretty simply:
It splits the string by - into words.
It maps each word into title case.
It joins the resulting words with spaces.
Do it in one line:
'athlete-profile'.split("-").join(" ").replace(/\w\S*/g, function(txt){return txt.charAt(0).toUpperCase() + txt.substr(1).toLowerCase()})
Output: Athlete Profile
The makeTitle() part of your question can be implemented something like this:
function makeTitle(thisID) {
return thisID.replace(/-/g, " ").replace(/\b[a-z]/g, function() {
return arguments[0].toUpperCase();
});
}
console.log(makeTitle("athlete-profile"))
The first .replace() changes all hyphens to spaces, and then the second .replace() takes any lower-case letter that follows a word boundary and makes it upper-case.
(For more information see the MDN doco for .replace().)
As far as doing it without using regular expressions, I'm not sure why you'd specifically want to avoid them, especially when the required expressions are pretty simple in this case (especially if you do the hyphen to space and first letter capitalisation in two steps as shown above). But there are endless ways to do this without regex using various combinations of JavaScript's string manipulation methods.
Do it like this
let someString = 'im a string';
console.log(someString.replace(/-/g, ' ')
.replace(/\w\S*/g, function (txt) {
return
txt.charAt(0).toUpperCase() + txt.substr(1).toLowerCase()
})
)
Output: Im A String
Short and great way:
const slugToText = (slug) => {
return slug.toLowerCase().replace(/-/g,' ')
}
Much Simplified answer
we can use String.prototype.replaceAll method to easily achieve this
function convertSlugToString(slug) {
return slug.replaceAll("-", " ");
}
incase you want to make sure the output is all lowercase then you can do the following
function convertSlugToString(slug) {
return slug.toLowerCase().replaceAll("-", " ");
}
Additional info:
String.prototype.replaceAll() is a ES2021 feature and it also has a great browser support with 93.64% global coverage, click here for more info
if you want to support IE then refer to the other answers
I would imagine this is a multiple part situation with regex, but how would you split a camelcase string at the capital letters turning them in to lowercase letters, and then adding a hyphen between each new string?
For example:
thisString
would become:
this-string
Try something like:
var myStr = 'thisString';
myStr = myStr.replace(/([a-z])([A-Z])/g, '$1-$2').toLowerCase();
Late to answer, but this solution will work for cases where a single letter is camel cased.
'thisIsATest'.replace(/([a-zA-Z])(?=[A-Z])/g, '$1-').toLowerCase(); // this-is-a-test
Try the following:
var token = document.getElementsByTagName('strong')[0].innerHTML,
replaced = token.replace(/[a-z][A-Z]/g, function(str, offset) {
return str[0] + '-' + str[1].toLowerCase();
});
alert(replaced);
Example - http://jsfiddle.net/7DV6A/2/
Documentation for the string replace function:
https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/String/replace
String.prototype.camelCaseToDashed = function(){
return this.replace(/([a-z])([A-Z])/g, '$1-$2').toLowerCase();
}
// Usage
"SomeVariable".camelCaseToDashed();
I don't know why all these solutions are so complex but i simply found this to be enough:
function camelCaseToDash(input){
// replace Capital letter with the letter + a dash: '-', then lowercase everything.
return input.replace(/([A-Z])/g, '-$1').toLowerCase();
}
//or, using a callback function, directly lowercasing.
function camelCaseToDashCallback(input){
//replace capital letter with lowercase variant + a dash '-'.
return input.replace(/([A-Z])/g, (x)=> "-"+ x.toLowerCase());
}
generally option 1 is faster though: https://jsfiddle.net/4557z/17/
How can I quickly validate if a string is alphabetic only, e.g
var str = "!";
alert(isLetter(str)); // false
var str = "a";
alert(isLetter(str)); // true
Edit : I would like to add parenthesis i.e () to an exception, so
var str = "(";
or
var str = ")";
should also return true.
Regular expression to require at least one letter, or paren, and only allow letters and paren:
function isAlphaOrParen(str) {
return /^[a-zA-Z()]+$/.test(str);
}
Modify the regexp as needed:
/^[a-zA-Z()]*$/ - also returns true for an empty string
/^[a-zA-Z()]$/ - only returns true for single characters.
/^[a-zA-Z() ]+$/ - also allows spaces
Here you go:
function isLetter(s)
{
return s.match("^[a-zA-Z\(\)]+$");
}
If memory serves this should work in javascript:
function containsOnlyLettersOrParenthesis(str)
(
return str.match(/^([a-z\(\)]+)$/i);
)
You could use Regular Expressions...
functions isLetter(str) {
return str.match("^[a-zA-Z()]+$");
}
Oops... my bad... this is wrong... it should be
functions isLetter(str) {
return "^[a-zA-Z()]+$".test(str);
}
As the other answer says... sorry