Syncerely

v1.0.0

A minimal library for serializing (a)synchronous tasks.

Installation

> npm i syncerely

Usage

syncerely provides the following interfaces:

• createSyncer()

First, import syncerely:

import * as syncerely from "syncerely";
import { functionInDemand } from "syncerely",

var syncer = require("syncerely");

Creates a serializer:

const syncer = createSyncer();

A Task is a function that accepts a complete() void function as the sole argument and call it somewhere. Calling the function is mandatory.

function task1(complete) {
    // some arbitrary actions
    console.log("task one finished.")
    complete();
}

function task2(complete) {
    new Promise((resolve, reject) => {
        // some arbitrary actions
    }).then((val) => {
        // some arbitrary actions
        console.log("task two finished.")
        complete();
    });
}

function task3(complete) { throw new Error(); }

function task4(complete) { console.log("task four finished."); };

Adds a task to the queue:

syncer.addTask(task1);
syncer.addTask(task2);
syncer.addTask(task3);
syncer.addTask(task4);

onOver() can be called with a void function with no parameter to be invoked at the end of the task queue when all the task are executed without any exceptions.

Sets an onOver() handler:

syncer.onOver(() => { console.log("All finished.") });

Similarly, onPanic() can be called with a void function with one Error parameter to be invoked when an exception arises. When an exception arises, syncer calls onPanic() and exits the queue by default. To continue to the next task, the handler should return true.

Sets an onPanic() handler:

syncer.onPanic((err) => { console.log("Just panicked!"); });

Another method intercept() is available for monitoring purposes. The function passed to the intercept() receives Syncer.Status type object, which contains the following values:

• isResolved - boolean : states whether any task is resolved,
• index - number : the index of the task that the serializer is waiting to be resolved or that has just been resolved,
• roundLeft - number : the number of times left to run the whole queue in repeat.

syncer.intercept((status) => {
    console.log(`
        We are at task ${status.index}\n
        that is ${
            status.isResolved
            ? "" : "being"
        } resolved.
        ${status.roundLeft} round(s) remaining.
    `);
});

Call run() to start executing the tasks in order. It accepts two parameters:

• repeat(optional) - number : the number of times the whole sequence should be run. Pass Infinity to run the queue repeatedly forever. (default: 1),
• every(optional) - number : delay between two consecutive iterations. Syncer uses setInterval() to loop over and wait for a task to be resolved and call the next task. This is the second parameter of that internal setInterval() (default: 0)

Runs the serialized tasks in order:

syncer.run();

> We are at task -1 that is resolved. 1 round(s) remaining.
> We are at task 0 that is being resolved. 1 round(s) remaining.
...
> "task one finished."
> We are at task 0 that is resolved. 1 round(s) remaining.
> We are at task 1 that is being resolved. 1 round(s) remaining.
...
> "task two finished."
> We are at task 1 that is resolved. 1 round(s) remaining.
> We are at task 2 that is being resolved. 1 round(s) remaining.
...
> "Just panicked!"
> [nothing about task four gets printed because the queue was terminated and we didn't return true in onPanic()]

License

The core files of the library are covered by MIT license.

All rights reserved. © 2023 Sai Aung Kyaw Htet

Dev-dependencies are covered by respective licenses and all the credits and copyrights go to respective authors.