Initial commit
This commit is contained in:
commit
ce055fa4c5
2
.gitignore
vendored
Normal file
2
.gitignore
vendored
Normal file
|
@ -0,0 +1,2 @@
|
|||
yarn.lock
|
||||
node_modules
|
44
README.md
Normal file
44
README.md
Normal file
|
@ -0,0 +1,44 @@
|
|||
# @joepie91/promise-delay-since
|
||||
|
||||
A function that, when called, produces a Promise that resolves a specified amount of milliseconds since a particular timestamp - or immediately, if the delay since that timestamp has already passed.
|
||||
|
||||
This is particularly useful when implementing rate-limiting and/or task distribution code - your implementation only has to track the timestamp of the last call, and leave it up to this module to decide when to resolve a Promise that kickstarts the next task.
|
||||
|
||||
## Example
|
||||
|
||||
See also `example.js` for a runnable version. This example uses Bluebird for `Promise.try` (read [this article](http://cryto.net/~joepie91/blog/2016/05/11/what-is-promise-try-and-why-does-it-matter/) to understand why), but Bluebird is not required to use this module.
|
||||
|
||||
```js
|
||||
"use strict";
|
||||
|
||||
const Promise = require("bluebird");
|
||||
const promiseDelaySince = require("@joepie91/promise-delay-since");
|
||||
|
||||
let startTimestamp = Date.now();
|
||||
|
||||
Promise.try(() => {
|
||||
// Logs immediately after running
|
||||
console.log("Hello world 1");
|
||||
|
||||
return promiseDelaySince(startTimestamp, 2000);
|
||||
}).then(() => {
|
||||
// Logs 2 seconds after running
|
||||
console.log("Hello world 2");
|
||||
|
||||
return promiseDelaySince(startTimestamp, 3000);
|
||||
}).then(() => {
|
||||
// Logs 3 seconds after running
|
||||
console.log("Hello world 3");
|
||||
});
|
||||
```
|
||||
|
||||
## API
|
||||
|
||||
### promiseDelaySince(sinceTimestamp, delay)
|
||||
|
||||
Creates a new Promise that will resolve `delay` milliseconds from the specified `sinceTimestamp`. If the current time is later than `sinceTimestamp + delay`, the returned Promise will resolve immediately.
|
||||
|
||||
- __sinceTimestamp:__ The reference timestamp to start counting from, as a 'UNIX timestamp' in milliseconds (like you get from `Date.now()`).
|
||||
- __delay:__ The delay as a number, in milliseconds.
|
||||
|
||||
The Promise will never reject.
|
22
example.js
Normal file
22
example.js
Normal file
|
@ -0,0 +1,22 @@
|
|||
"use strict";
|
||||
|
||||
const Promise = require("bluebird");
|
||||
|
||||
const promiseDelaySince = require("./");
|
||||
|
||||
let startTimestamp = Date.now();
|
||||
|
||||
Promise.try(() => {
|
||||
// Logs immediately after running
|
||||
console.log("Hello world 1");
|
||||
|
||||
return promiseDelaySince(startTimestamp, 2000);
|
||||
}).then(() => {
|
||||
// Logs 2 seconds after running
|
||||
console.log("Hello world 2");
|
||||
|
||||
return promiseDelaySince(startTimestamp, 3000);
|
||||
}).then(() => {
|
||||
// Logs 3 seconds after running
|
||||
console.log("Hello world 3");
|
||||
});
|
16
index.js
Normal file
16
index.js
Normal file
|
@ -0,0 +1,16 @@
|
|||
"use strict";
|
||||
|
||||
module.exports = function promiseDelaySince(previousTimestamp, delay) {
|
||||
return new Promise((resolve, reject) => {
|
||||
let targetTime = previousTimestamp + delay;
|
||||
let currentTime = Date.now();
|
||||
|
||||
if (currentTime > targetTime) {
|
||||
resolve();
|
||||
} else {
|
||||
setTimeout(() => {
|
||||
resolve();
|
||||
}, targetTime - currentTime);
|
||||
}
|
||||
});
|
||||
};
|
11
package.json
Normal file
11
package.json
Normal file
|
@ -0,0 +1,11 @@
|
|||
{
|
||||
"name": "@joepie91/promise-delay-since",
|
||||
"version": "1.0.0",
|
||||
"main": "index.js",
|
||||
"repository": "git@git.cryto.net:joepie91/node-promise-delay-since.git",
|
||||
"author": "Sven Slootweg <admin@cryto.net>",
|
||||
"license": "WTFPL OR CC0-1.0",
|
||||
"devDependencies": {
|
||||
"bluebird": "^3.5.4"
|
||||
}
|
||||
}
|
Loading…
Reference in a new issue