eorroe/String.prototype.contains

Checks if at least one string in passed array is included in string

String.prototype.contains proposal

Problem

Let's say I want to check whether a string contains at least one other string from many:

In ES5

var str = 'Hello this is a string';

// Using regex:
/Hello|is/.test(str); // true

// Using good old indexOf
str.indexOf('Hello') > -1 || str.indexOf('is'); // true

// Using ES6 (String.prototype.includes)
str.includes('Hello') || str.includes('is'); // true

So what happens if I want to do this with a bunch of strings String.prototype.contains to the rescue:

Solution

var str = 'Hello this is a string';

str.contains(['Hello', 'is']); // true

//Let's add a string that it's not a part of str
str.contains(['Hello', 'is', 'notInString']) // true

So contains checks if at least one of the strings in the array are a part of the string that contains is being called on.

var str = 'Hello this is a string';

// Passing an array of strings where none are included in string that contains is called on
str.contains(['notInString']); // false

String.prototype.contains has a second parameter which is the index from where to check if any of the strings in the array are included:

var str = 'Hello this is a string';

// As before
str.contains(['Hello']); // true
// With Index
str.contains(['Hello'], 1); // false

// Multiple strings

// As before
str.contains(['Hello', 'is']); // true
// With Index
str.contains(['Hello', 'is'], 1); // true

Check out String.prototype.containsAll proposal

Here's the former discussion on ES-Discuss