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40 lines
989 B
40 lines
989 B
13 years ago
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module.exports = promiseChain
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// usage:
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//
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// promiseChain(cb) <-- this is the callback for eventual success or error
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// ( fn, [arg, arg, arg], function (a,b,c) { success(a,b,c) })
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// ( fn2, [args] )
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// () <-- this kicks it off.
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//
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// promiseChain.call(someObj, cb) <-- bind this-context for all functions
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function promiseChain (cb) {
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var steps = []
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, vals = []
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, context = this
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function go () {
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var step = steps.shift()
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if (!step) return cb()
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try { step[0].apply(context, step[1]) }
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catch (ex) { cb(ex) }
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}
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return function pc (fn, args, success) {
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if (arguments.length === 0) return go()
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// add the step
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steps.push
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( [ fn
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, (args || []).concat([ function (er) {
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if (er) return cb(er)
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var a = Array.prototype.slice.call(arguments, 1)
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try { success && success.apply(context, a) }
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catch (ex) { return cb(ex) }
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go()
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}])
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]
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)
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return pc
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}
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}
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