var _getLength = require('./_getLength.js');
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var _isArrayLike = require('./_isArrayLike.js');
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var isArray = require('./isArray.js');
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var isArguments = require('./isArguments.js');
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// Internal implementation of a recursive `flatten` function.
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function flatten(input, depth, strict, output) {
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output = output || [];
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if (!depth && depth !== 0) {
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depth = Infinity;
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} else if (depth <= 0) {
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return output.concat(input);
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}
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var idx = output.length;
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for (var i = 0, length = _getLength(input); i < length; i++) {
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var value = input[i];
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if (_isArrayLike(value) && (isArray(value) || isArguments(value))) {
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// Flatten current level of array or arguments object.
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if (depth > 1) {
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flatten(value, depth - 1, strict, output);
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idx = output.length;
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} else {
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var j = 0, len = value.length;
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while (j < len) output[idx++] = value[j++];
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}
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} else if (!strict) {
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output[idx++] = value;
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}
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}
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return output;
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}
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module.exports = flatten;
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