[JAVASCRIPT] array method(part2)

//Array.of() 메서드는 인자의 수나 유형에 관계없이 가변 인자를 갖는 새 Array 인스턴스를 만듭니다. Array(7); // [ , , , , , , ] Array.of(7); // [1] Array.of(1, 2, 3); // [1, 2, 3] //ie 미지원 if (!Array.of) { Array.of = function() { return Array.prototype.slice.call(arguments); }; } arr.fill(value[, start[, end]]) //value 값을 start index부터 end index까지 채워 넣는다 //start 기본값 : 0, end 기본값 : this.length var array1 = [1, 2, 3, 4]; array1.fill(0, 2, 4); // expected output: [1, 2, 0, 0] array1.fill(5, 1); // expected output: [1, 5, 5, 5] array1.fill(6); // expected output: [6, 6, 6, 6] var arr = Array(3).fill({}); // [{}, {}, {}] arr[0].hi = "hi"; // [{ hi: "hi" }, { hi: "hi" }, { hi: "hi" }] //출처 : https://developer.mozilla.org/ko/docs/Web/JavaScript/Reference/Global_Objects/Array/of //ie 미지원 if (!Array.prototype.fill) { Object.defineProperty(Array.prototype, 'fill', { value: function(value) { // Steps 1-2. if (this == null) { throw new TypeError('this is null or not defined'); } var O = Object(this); // Steps 3-5. var len = O.length >>> 0; // Steps 6-7. var start = arguments[1]; var relativeStart = start >> 0; // Step 8. var k = relativeStart < 0 ? Math.max(len + relativeStart, 0) : Math.min(relativeStart, len); // Steps 9-10. var end = arguments[2]; var relativeEnd = end === undefined ? len : end >> 0; // Step 11. var final = relativeEnd < 0 ? Math.max(len + relativeEnd, 0) : Math.min(relativeEnd, len); // Step 12. while (k < final) { O[k] = value; k++; } // Step 13. return O; } }); } //출처 : https://developer.mozilla.org/ko/docs/Web/JavaScript/Reference/Global_Objects/Array/fill [1, 2, 3].includes(2); // true [1, 2, 3].includes(4); // false //ie 미지원 // https://tc39.github.io/ecma262/#sec-array.prototype.includes if (!Array.prototype.includes) { Object.defineProperty(Array.prototype, 'includes', { value: function(searchElement, fromIndex) { if (this == null) { throw new TypeError('"this" is null or not defined'); } // 1. Let O be ? ToObject(this value). var o = Object(this); // 2. Let len be ? ToLength(? Get(O, "length")). var len = o.length >>> 0; // 3. If len is 0, return false. if (len === 0) { return false; } // 4. Let n be ? ToInteger(fromIndex). // (If fromIndex is undefined, this step produces the value 0.) var n = fromIndex | 0; // 5. If n ≥ 0, then // a. Let k be n. // 6. Else n < 0, // a. Let k be len + n. // b. If k < 0, let k be 0. var k = Math.max(n >= 0 ? n : len - Math.abs(n), 0); function sameValueZero(x, y) { return x === y || (typeof x === 'number' && typeof y === 'number' && isNaN(x) && isNaN(y)); } // 7. Repeat, while k < len while (k < len) { // a. Let elementK be the result of ? Get(O, ! ToString(k)). // b. If SameValueZero(searchElement, elementK) is true, return true. if (sameValueZero(o[k], searchElement)) { return true; } // c. Increase k by 1. k++; } // 8. Return false return false; } }); } //출처 : https://developer.mozilla.org/ko/docs/Web/JavaScript/Reference/Global_Objects/Array/includes