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