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An example "always" behavior for ES6 promises. This only works if you do not create / return intermediate promises.
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| // A thing I want to do | |
| // This flow only involves **one** promise, for example an ajax call | |
| // None of the subsequent `then` or `catch` calls, return new promises. | |
| const explode = false; | |
| const promise = new Promise((resolve, reject) => { | |
| if (explode) { | |
| reject(); | |
| } else { | |
| resolve(); | |
| } | |
| }).then(() => { | |
| console.log('Thing is done. Do followup task.'); | |
| return 'my argument'; | |
| }).then((arg1) => { | |
| console.log('Thing is done. Do followup task 2. argument: ' + arg1); | |
| }).catch(() => { | |
| console.log('Thing failed'); | |
| }).then(() => { | |
| console.log('Always do this'); | |
| }); | |
| // => "Thing is done. Do followup task." | |
| // => "Thing is done. Do followup task 2. argument: my argument" | |
| // => "Always do this" | |
| // Set explode to true | |
| const explode = true; | |
| const promise = new Promise((resolve, reject) => { | |
| if (explode) { | |
| reject(); | |
| } else { | |
| resolve(); | |
| } | |
| }).then(() => { | |
| console.log('Thing is done. Do followup task.'); | |
| return 'my argument'; | |
| }).then((arg1) => { | |
| console.log('Thing is done. Do followup task 2. argument: ' + arg1); | |
| }).catch(() => { | |
| console.log('Thing failed'); | |
| }).then(() => { | |
| console.log('Always do this'); | |
| }); | |
| // => "Thing failed" | |
| // => "Always do this" |
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