46 lines
1.4 KiB
Markdown
46 lines
1.4 KiB
Markdown
---
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title: Promise Resolve
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---
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## Promise Resolve
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### Description
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A ```Promise.resolve``` function indicates the successful completion of a Promise. This function allows you to return a Promise to the calling function.
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```Promise.resolve``` takes a single parameter to return to the calling function. This parameter can either be a value, a thenable, or another Promise.
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A "value" for a resolve function can be basic JavaScript types, arrays, or objects.
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```javascript
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Promise.resolve('success'); // string
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Promise.resolve([2, 3, 5]); // array
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Promise.resolve({name: 'John', age: '43'}); // object
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```
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A "thenable" is a function that takes two callback functions as parameters. You can use the first parameter to trigger a successful completion, and the second to return an error on the Promise.
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```javascript
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thenableFunction = {then: function(onSuccesss, onFailure) {
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if (condition === 'success') {
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onSuccess(paramList); // success condition
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} else {
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onFailure(paramList); // error condition
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}
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}
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}
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Promise.resolve(thenableFunction);
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```
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Chaining a then function to a promise caller will give you access to the result of ```Promise.resolve```.
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```javascript
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promiseCallingFunction(paramList)
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.then(function(value) {
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/*
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* this is where you get access to the value
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* returned by a promise on successful completion
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*/
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});
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```
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