import isArguments from './isArguments.js'; import isBuffer from './isBuffer.js'; import isIndex from './isIndex.js'; import isTypedArray from './isTypedArray.js'; /** Used to check objects for own properties. */ /** 用于检查对象的自身属性。 */ const hasOwnProperty = Object.prototype.hasOwnProperty; /** * Creates an array of the enumerable property names of the array-like `value`. * 创建类似数组的“值”的可枚举属性名的数组。 * @private * @param {*} value 要查询的值. * @param {boolean} inherited 指定返回继承的属性名. * @returns {Array} 返回属性名数组. */ function arrayLikeKeys(value, inherited) { const isArr = Array.isArray(value); const isArg = !isArr && isArguments(value); const isBuff = !isArr && !isArg && isBuffer(value); const isType = !isArr && !isArg && !isBuff && isTypedArray(value); const skipIndexes = isArr || isArg || isBuff || isType; const length = value.length; const result = new Array(skipIndexes ? length : 0); let index = skipIndexes ? -1 : length; while (++index < length) { result[index] = `${index}`; } for (const key in value) { if ( (inherited || hasOwnProperty.call(value, key)) && !( skipIndexes && // Safari 9 has enumerable `arguments.length` in strict mode. (key === 'length' || // Skip index properties. isIndex(key, length)) ) ) { result.push(key); } } return result; } export default arrayLikeKeys;