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34 lines
905 B
JavaScript
34 lines
905 B
JavaScript
8 months ago
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// Returns a wrapper function that returns a wrapped callback
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// The wrapper function should do some stuff, and return a
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// presumably different callback function.
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// This makes sure that own properties are retained, so that
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// decorations and such are not lost along the way.
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module.exports = wrappy
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function wrappy (fn, cb) {
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if (fn && cb) return wrappy(fn)(cb)
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if (typeof fn !== 'function')
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throw new TypeError('need wrapper function')
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Object.keys(fn).forEach(function (k) {
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wrapper[k] = fn[k]
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})
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return wrapper
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function wrapper() {
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var args = new Array(arguments.length)
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for (var i = 0; i < args.length; i++) {
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args[i] = arguments[i]
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}
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var ret = fn.apply(this, args)
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var cb = args[args.length-1]
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if (typeof ret === 'function' && ret !== cb) {
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Object.keys(cb).forEach(function (k) {
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ret[k] = cb[k]
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})
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}
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return ret
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}
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}
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