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'use strict';
var isPlainArray = require('../../is-plain-array')
, toPosInt = require('../../../number/to-pos-integer')
, isObject = require('../../../object/is-object')
, isArray = Array.isArray, concat = Array.prototype.concat
, forEach = Array.prototype.forEach
, isSpreadable;
isSpreadable = function (value) {
if (!value) return false;
if (!isObject(value)) return false;
if (value['@@isConcatSpreadable'] !== undefined) {
return Boolean(value['@@isConcatSpreadable']);
}
return isArray(value);
};
module.exports = function (item/*, …items*/) {
var result;
if (!this || !isArray(this) || isPlainArray(this)) {
return concat.apply(this, arguments);
}
result = new this.constructor(this.length);
forEach.call(this, function (val, i) { result[i] = val; });
forEach.call(arguments, function (arg) {
var base;
if (isSpreadable(arg)) {
base = result.length;
result.length += toPosInt(arg.length);
forEach.call(arg, function (val, i) { result[base + i] = val; });
return;
}
result.push(arg);
});
return result;
};
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