55 lines
1 KiB
JavaScript
55 lines
1 KiB
JavaScript
'use strict'
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var nextTick = nextTickArgs
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process.nextTick(upgrade, 42) // pass 42 and see if upgrade is called with it
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module.exports = thunky
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function thunky (fn) {
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var state = run
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return thunk
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function thunk (callback) {
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state(callback || noop)
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}
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function run (callback) {
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var stack = [callback]
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state = wait
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fn(done)
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function wait (callback) {
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stack.push(callback)
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}
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function done (err) {
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var args = arguments
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state = isError(err) ? run : finished
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while (stack.length) finished(stack.shift())
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function finished (callback) {
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nextTick(apply, callback, args)
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}
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}
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}
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}
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function isError (err) { // inlined from util so this works in the browser
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return Object.prototype.toString.call(err) === '[object Error]'
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}
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function noop () {}
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function apply (callback, args) {
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callback.apply(null, args)
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}
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function upgrade (val) {
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if (val === 42) nextTick = process.nextTick
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}
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function nextTickArgs (fn, a, b) {
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process.nextTick(function () {
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fn(a, b)
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})
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}
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