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https://github.com/camel-chased/promiseloop
for testing nested promises
https://github.com/camel-chased/promiseloop
jasmine nested-promises promise promises test testing tests
Last synced: 20 days ago
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for testing nested promises
- Host: GitHub
- URL: https://github.com/camel-chased/promiseloop
- Owner: camel-chased
- Created: 2017-02-24T23:06:20.000Z (almost 8 years ago)
- Default Branch: master
- Last Pushed: 2017-02-26T18:36:46.000Z (almost 8 years ago)
- Last Synced: 2024-11-05T10:03:14.010Z (2 months ago)
- Topics: jasmine, nested-promises, promise, promises, test, testing, tests
- Language: JavaScript
- Size: 7.81 KB
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.MD
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README
# promiseloop
This package was developed to resolve testing issues with nested promises and timing mocks but can be used elsewhere as well - it is kind of generous.
With this module you can test something on each level of `Promise.then` with multiple promises run simultanousely.
It can be used to check something on each level of `then` method.
`then` method is executed in most cases with `setImmediate` or `process.nextTick` so it is hard to test future "ticks" in synchronous way for example setTimeout inside `then` will not be catched by timer mocks because `setTimeout` inside `then` will be fired in the future (ticks).
`promiseloop` is going through all levels of ticks and can catch all those `setTimout`s or other things that are executed in next (future) ticks.
Here you can read about the problem: http://stackoverflow.com/questions/42446795/how-to-use-jasmine-clock-settimeout-in-nested-promises-when-order-matters-ja
## usage
```
npm install promiseloop
let promiseLoop = require('promiseloop')(Promise);
// where Promise is your Promise implementation
```
```javascript
let levelsDeep = 10; // how deep we want to go through 'then' levels?
function iterationFn(){
// this function will be executed in each level of 'then'
// each level of 'then' is in most cases something like setImmediate or nextTick
}
function finalFn(){
// this function will be executed at the end of the chain - final
}
promiseLoop(levelsDeep,iterationFn,finalFn);
```
we can only have finalFn instead of iteration
```javascript
let levelsDeep = 10; // how deep we want to go through 'then' levels?
function finalFn(){
// this function will be executed at the end of the chain - final
}
promiseLoop(levelsDeep,finalFn);
```
For example if you need to test multiple promises and you does not want to make sophisticated algorithm to check that everything is already executed on each level.
```javascript
let testNr=0;
new Promise((resolve,reject)=>{
resolve("ok");
}).then(()=>{
// level 1
testNr++; // 1
}).then(()=>{
// level 2
testNr++; // 3
});
new Promise((resolve,reject)=>{
resolve("ok");
}).then(()=>{
// level 1
testNr++; // 2
}).then(()=>{
// level 2
testNr++; // 4
});
function each(currentLevel){
if(currentLevel==1){
expect(testNr).toEqual(2);
}else if(currentLevel==2){
expect(testNr).toEqual(4);
}
}
function final(){
expect(testNr).toEqual(4);
done();
}
promiseLoop(3,each,final);
```