javascript string startswith

1var str = "Hello world, welcome to the universe.";
2var n = str.startsWith("Hello");

1const str = "Saturday night plans";
2const res = str.startsWith("Sat");
3console.log(res); //> true

1const str1 = 'Saturday night plans';
2
3console.log(str1.startsWith('Sat'));
4// expected output: true
5
6console.log(str1.startsWith('Sat', 3));
7// expected output: false
8

1//checks if a string starts with a word
2function startsWith(str, word) {
3    return str.lastIndexOf(word, 0) === 0;
4}
5startsWith("Welcome to earth.","Welcome"); //true

1const s = 'I am going to become a FULL STACK JS Dev with Coderslang';
2
3console.log(s.startsWith('I am'));             // true
4console.log(s.startsWith('You are'));          // false

1if (!String.prototype.startsWith) {
2    Object.defineProperty(String.prototype, 'startsWith', {
3        value: function(search, rawPos) {
4            var pos = rawPos > 0 ? rawPos|0 : 0;
5            return this.substring(pos, pos + search.length) === search;
6        }
7    });
8}
9