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adamloving/promise-chain-catch.coffee

Last active September 24, 2015 18:08
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When using when.js, should you put the catch first or last in the promise chain?
Raw
promise-chain-catch.coffee
w = require 'when'
# When using when, should you put the catch first or last in the promise chain?
# You should put it last if you want it to end the chain before your thens run.
doSomethingAndFail = (n) ->
console.log 'fail', n
w.reject(n)
doSomethingAndFail(1)
.then (n) ->
console.log 'then after fail', n # never runs
.catch (n) ->
console.log 'caught failure at end of chain', n
doSomethingAndFail(2)
.catch (n) ->
console.log 'caught failure at beginning of chain', n
.then (n) ->
console.log 'then after catch', n # runs with n == undefined
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