README

Command invoker

A very simple command invoker + memento pattern implementation in Typescript. Actions are broken down into commands. Invoker invokes commands. Invoker remembers invoked commands and allows undo, redo.

there is no upper limit on the amount of commands the invoker remembers
when you do multiple undo() and then invoke(), all redos vanish (i.e. classic behavior)
when there is nothing else to undo, the undo() method simply does nothing (the same goes for redo(), i.e. classic behavior)

API

import { Command, CommandInvoker, MultiCommand } from 'ts-command-invoker';

/**
 * Your commands inherit from it.
 * You pass your data to the command via your custom constructor.
 */
Command
    .do()
    .redo()

/**
 * Invokes commands and remembers them in order to provide undo and redo.
 * Throws if undo is called when there is nothing to undo (same for redo).
 */
CommandInvoker
    .invoke(command)
    .undo()
    .redo()

/**
 * Sometimes you want multiple commands executed at once (eg. delete and unselect),
 * MultiCommand takes this array of commands and executes them in the correct order (same for undo)
 */
MultiCommand
    constructor(command[])

Install

npm i ts-command-invoker

Examples and tests

Everything is nicely tested. If you want to learn more, look at examples in /examples and test in /src/*test.ts.

Licence

Feel free to use in any way. (ISC)

Footnotes: How to publish typescript to npm

It's a bit tricky. Pure typescript cannot be published, because webpack, etc. do not compile the code of libraries. (After install this results in the cryptic error: package not found; no idea why)

// index.ts exports all exports
npm i typescript --save-dev
package.json > scripts: build: "tsc"
npm run build
package.json > main: dist/index.js; types: dist/index.d.ts
package.json > version ++
npm adduser
npm publish

Usage no npm install needed!