ngrx-undo

Simple middleware for adding undo capability to @ngrx/store

Install

npm install xes-ngrx-undo

Usage

import { undoBehavior } from 'xes-ngrx-undo';

// for AoT
const undoBehaviorReducerDecorator = undoBehavior(100);
export function undoBehaviorReducer(rootReducer: any) {
  return undoBehaviorReducerDecorator(rootReducer);
}

@NgModule({
  imports: [
    // initialize buffor size on creation
    StoreModule.provideStore(rootReducer, { metaReducers: [undoBehaviorReducer] })
  ]
})
export class AppModule { }

After initializing StoreModule you can use undo action factory like this:

import { undo } from "ngrx-undo";

// create action
let action = { type: 'ADD', value: 10 }

// dispatch base action
this.store.dispatch(action);

// dispatch undo action
this.store.dispatch(undo(action));

This will undo last action that has similar object to structure to action.

Simple undo redo manager example

export class UndoRedoManager<T> {
  redoActions: any[] = [];
  undoActions: any[] = [];

  constructor(private store: Store<T>) {}

  /**
   * To be safe all actions should pass by it.
   */
  dispatch(action) {
    // you can filter actions 
    this.undoActions.push(action);
    this.redoActions = [];
    this.store.dispatch(action);
  }

  undo(): boolean {
    if (this.undoActions.length > 0) {
      const action = this.undoActions.pop();
      this.redoActions.push(action);
      this.store.dispatch(undo(action));

      return true;
    }

    return false;
  }

  /**
   * This one pushes action to end of actions queue so its a bit ify if they were removed somewhere deeper down the queue
   */
  redo(): boolean {
    if (this.redoActions.length > 0) {
      const action = this.redoActions.pop();
      this.undoActions.push(action);
      this.store.dispatch(action);

      return true;
    }

    return false;
  }
}

Contribution

Features

• Zero-setup. After running npm install things will be setup for you :wink:
• RollupJS for multiple optimized bundles following the standard convention and Tree-shaking.
• Tests, coverage and interactive watch mode using Jest
• Prettier and TSLint for code formatting and consistency.
• Docs automatic generation and deployment to gh-pages, using TypeDoc
• Automatic types (*.d.ts) file generation
• Travis integration and Coveralls report
• (Optional) Automatic releases and changelog, using Semantic release, Commitizen, Conventional changelog and Husky (for the git hooks)

NPM scripts

• npm t: Run test suite
• npm start: Runs npm run build in watch mode
• npm run test:watch: Run test suite in interactive watch mode
• npm run test:prod: Run linting and generate coverage
• npm run build: Generate bundles and typings, create docs
• npm run lint: Lints code
• npm run commit: Commit using conventional commit style (husky will tell you to use it if you haven't :wink:)

Automatic releases

If you'd like to have automatic releases with Semantic Versioning, follow these simple steps.

Prerequisites: you need to create/login accounts and add your project to:

• npm
• Travis
• Coveralls

Run the following command to prepare hooks and stuff:

npm run semantic-release-prepare

Follow the console instructions to install semantic release and run it (answer NO to "Generate travis.yml").

Note: make sure you've setup repository.url in your package.json file

npm install -g semantic-release-cli
semantic-release setup
# IMPORTANT!! Answer NO to "Generate travis.yml" question. It is already prepared for you :P

From now on, you'll need to use npm run commit, which is a convenient way to create conventional commits.

Automatic releases are possible thanks to semantic release, which publishes your code automatically on Github and npm, plus generates a changelog automatically. This setup is highly influenced by Kent C. Dodds course on egghead.io

Resources

• Write a library using TypeScript library starter by @alexjoverm
• 📺 Create a TypeScript Library using typescript-library-starter by @alexjoverm
• Introducing TypeScript Library Starter Lite by @tonysneed

Credits

Library made with use of TypeScript library starter