44 lines
1.2 KiB
JavaScript
44 lines
1.2 KiB
JavaScript
"use strict";
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var isPlainArray = require("../../is-plain-array")
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, toPosInt = require("../../../number/to-pos-integer")
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, isObject = require("../../../object/is-object")
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, isConcatSpreadable = require("es6-symbol").isConcatSpreadable
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, isArray = Array.isArray
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, concat = Array.prototype.concat
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, forEach = Array.prototype.forEach
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, isSpreadable;
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isSpreadable = function (value) {
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if (!value) return false;
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if (!isObject(value)) return false;
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if (value[isConcatSpreadable] !== undefined) {
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return Boolean(value[isConcatSpreadable]);
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}
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return isArray(value);
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};
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// eslint-disable-next-line no-unused-vars
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module.exports = function (item/*, …items*/) {
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var result;
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if (!this || !isArray(this) || isPlainArray(this)) {
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return concat.apply(this, arguments);
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}
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result = new this.constructor();
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if (isSpreadable(this)) {
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forEach.call(this, function (val, i) { result[i] = val; });
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} else {
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result[0] = this;
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}
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forEach.call(arguments, function (arg) {
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var base;
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if (isSpreadable(arg)) {
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base = result.length;
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result.length += toPosInt(arg.length);
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forEach.call(arg, function (val, i) { result[base + i] = val; });
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return;
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}
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result.push(arg);
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});
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return result;
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};
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