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string

format

  • >= ES6
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let soMany = 10;
console.log(`This is ${soMany} times easier!`);
// "This is 10 times easier!

if (!String.prototype.format) {
  String.prototype.format = function() {
    var args = arguments;
    return this.replace(/{(\d+)}/g, function(match, number) { 
      return typeof args[number] != 'undefined'
        ? args[number]
        : match
      ;
    });
  };
}

Find

  • indexOf()/lastIndexOf()
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var str = "Please locate where 'locate' occurs! locate";
var first_pos = str.indexOf("locate");
var last_pos = str.lastIndexOf("locate");

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let str = '...';
const regex = /ab+c/g;
let pos = str.search(regex);

Splice, Substr

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var str = "Apple, Banana, Kiwi";

str.slice(7, 13);   // Banana
str.slice(-12, -6); // Banana

str.slice(7);       // Banana, Kiwi
str.slice(-4);      // Kiwi

str.substr(7, 6);   // Banana
str.substr(7);      // Banana, Kiwi

str.substr(-12, 6); // Banana
str.substr(-4);     // Kiwi

Replace

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let str = "Apple, Banana, Kiwi, Banana";
let a = str.replace("Banana", "PP");  // Apple, PP, Kiwi, Banana
let b = str.replace(/Banana/g, "PP"); // Apple, PP, Kiwi, PP

Uppercase and Lowercase

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let str = "Hello World!";
let a = str.toUpperCase(); // HELLO WORLD!
let b = str.toLowerCase(); // hello world!

Concate

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var a = "Hello";
var b = "World";
var c = a.concat(" ", b); // Hello World

Trim

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let str = "       Hello World!        ";
let a = str.trim(); // "Hello World!"

Padding

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let str = "5";
let a = str.padStart(4, 0); // 0005
let b = str.padEnd(4, 0);   // 5000

Access

Danger

str[] is read-only in javascript. string != array in javascript.

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let str = "ABCDE";
str.charAt(0);    // A
str.charCodeAt(0) // 72
str[0]            // A

Split

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let str = "a,b,c,d,e";
let a = str.split(","); // ["a","b","c","d","e"]
// str.split(/regex/)