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26 lines
759 B
JavaScript
26 lines
759 B
JavaScript
6 years ago
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/** Used as references for various `Number` constants. */
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var MAX_SAFE_INTEGER = 9007199254740991;
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/** Used to detect unsigned integer values. */
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var reIsUint = /^(?:0|[1-9]\d*)$/;
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/**
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* Checks if `value` is a valid array-like index.
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*
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* @private
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* @param {*} value The value to check.
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* @param {number} [length=MAX_SAFE_INTEGER] The upper bounds of a valid index.
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* @returns {boolean} Returns `true` if `value` is a valid index, else `false`.
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*/
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function isIndex(value, length) {
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var type = typeof value;
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length = length == null ? MAX_SAFE_INTEGER : length;
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return !!length &&
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(type == 'number' ||
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(type != 'symbol' && reIsUint.test(value))) &&
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(value > -1 && value % 1 == 0 && value < length);
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}
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module.exports = isIndex;
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