28 lines
886 B
JavaScript
28 lines
886 B
JavaScript
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define(function () {
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// Internal function that returns an efficient (for current engines) version
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// of the passed-in callback, to be repeatedly applied in other Underscore
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// functions.
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function optimizeCb(func, context, argCount) {
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if (context === void 0) return func;
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switch (argCount == null ? 3 : argCount) {
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case 1: return function(value) {
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return func.call(context, value);
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};
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// The 2-argument case is omitted because we’re not using it.
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case 3: return function(value, index, collection) {
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return func.call(context, value, index, collection);
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};
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case 4: return function(accumulator, value, index, collection) {
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return func.call(context, accumulator, value, index, collection);
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};
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}
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return function() {
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return func.apply(context, arguments);
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};
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}
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return optimizeCb;
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});
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