32 lines
1.1 KiB
JavaScript
32 lines
1.1 KiB
JavaScript
define(['./_getLength', './isFunction'], function (_getLength, isFunction) {
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// Internal function for linearly iterating over arrays.
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function linearSearch(array, predicate, dir, start) {
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var target, length = _getLength(array);
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dir || (dir = 1);
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start = (
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start == null ? (dir > 0 ? 0 : length - 1) :
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start < 0 ? (dir > 0 ? Math.max(0, start + length) : start + length) :
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dir > 0 ? start : Math.min(start, length - 1)
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);
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// As a special case, in order to elide the `predicate` invocation on every
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// loop iteration, we allow the caller to pass a value that should be found by
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// strict equality comparison. This is somewhat like a rudimentary iteratee
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// shorthand. It is used in `_.indexof` and `_.lastIndexOf`.
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if (!isFunction(predicate)) {
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target = predicate && predicate.value;
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predicate = false;
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}
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for (; start >= 0 && start < length; start += dir) {
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if (
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predicate ? predicate(array[start], start, array) :
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array[start] === target
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) return start;
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}
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return -1;
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}
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return linearSearch;
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});
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