startswith() javascript code example

Example 1: js startswith

var str = "Hello world, welcome to the universe.";
var n = str.startsWith("Hello");

Example 2: js startswith

const str1 = 'Saturday night plans';

console.log(str1.startsWith('Sat'));
// expected output: true

console.log(str1.startsWith('Sat', 3));
// expected output: false

Example 3: javascript string starts with

//checks if a string starts with a word
function startsWith(str, word) {
    return str.lastIndexOf(word, 0) === 0;
}
startsWith("Welcome to earth.","Welcome"); //true

Example 4: javascript multiple startswith

//There is NO possibility to passing an Array
//like startsWith(["Mon" | "Tues"])
if (newStr4.startsWith("Mon") || newStr4.startsWith("Tues") || ...)

//although you can use regular expression,
//but performance are lower than the solution above
 if (newStr4.matches("(Mon|Tues|Wed|Thurs|Fri).*"))

Example 5: javascript string starts with

const s = 'I am going to become a FULL STACK JS Dev with Coderslang';

console.log(s.startsWith('I am'));             // true
console.log(s.startsWith('You are'));          // false