31 lines
872 B
Markdown
31 lines
872 B
Markdown
---
|
|
title: hashNode
|
|
tags: node,promise,advanced
|
|
---
|
|
|
|
Creates a hash for a value using the [SHA-256](https://en.wikipedia.org/wiki/SHA-2) algorithm.
|
|
Returns a promise.
|
|
|
|
- Use `crypto.createHash()` to create a `Hash` object with the appropriate algorithm.
|
|
- Use `hash.update()` to add the data from `val` to the `Hash`, `hash.digest()` to calculate the digest of the data.
|
|
- Use `setTimeout()` to prevent blocking on a long operation, and return a `Promise` to give it a familiar interface.
|
|
|
|
```js
|
|
const crypto = require('crypto');
|
|
|
|
const hashNode = val =>
|
|
new Promise(resolve =>
|
|
setTimeout(
|
|
() => resolve(crypto.createHash('sha256').update(val).digest('hex')),
|
|
0
|
|
)
|
|
);
|
|
```
|
|
|
|
```js
|
|
hashNode(JSON.stringify({ a: 'a', b: [1, 2, 3, 4], foo: { c: 'bar' } })).then(
|
|
console.log
|
|
);
|
|
// '04aa106279f5977f59f9067fa9712afc4aedc6f5862a8defc34552d8c7206393'
|
|
```
|