@silexlabs/expression-input

v0.0.25

Published

9 days ago

A web component to include in your JS/TS projects. Your users can create an expression or a ordoned list with your data tree.

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jbips

lexoyo

web-components lit-element typescript lit

Expression Input web component

A web component to include in your JS/TS projects. Your users can create an expression which is a ordoned list of tokens. It feels like auto completion without typing text. The token can have options too.

This web component implements the same API as HTML inputs so it can be used inside a <form>, with support of the FormData API. It supports focus and keyboard navigation too.

This is part of a bigger project: Silex no-code website builder

This feature is made of these components

[x] <popin-overlay> behaves like a popin, disapears when it loses focus
[x] <popin-form> extends the <popin-overlay> component, behaves both like a form with the inputs inside it and like an input for a parent form
[x] <expression-input> handles "fixed value" which is a simple text input and "expression" which is an editable list of tokens

Use cases

Build an expression the no-code way - e.g. obj.prop1.subProp (js), posts | where: 'id', '123' (liquidjs)
Select a folder in a file system
Make decisions in a decision tree
Edit a list of tokens

Roadmap

Project

[x] Automated publish to npm with github action
[ ] Unit tests still fail on github actions (playwrite issue)

Popin

[x] Display where placed
[x] Handle focus

ExpressionInput

[x] values: icon, name (may be a function of options), tags, options, optionsForm, type, helpText (with html links to directus collection)
[x] callback getNextChoices(pastChoices)
[x] message (if error or warning)
[x] events: change
[x] styling
[ ] copy / paste / set / unset
[ ] result (the final value resulting the current choices)
[ ] state: valid, warning, error
[x] helpText

Integration guide

Install the npm package in your project

$ npm install --save @silexlabs/expression-input

Include the library with ESNext import "@silexlabs/expression-input" or directly in the HTML with <script src="/path/to/expression-input.js"></script>

Use in your HTML as a web component:

<html>
  <body>
    <expression-input
      name="form-data-name"
      onload="event => console.log(event.target)"
      onchange="event => console.log('onchange', event)"
    >
      <span slot="label">Test label</span>
      <select>
          <option value="">+</option>
          <option value="Blog Post" selected>Blog Post</option>
          <option value="Page">Page</option>
          <option value="Settings">Settings</option>
      </select>
    </expression-input>
  </body>
</html>

Check the files in /dev/ folder for examples.

API

The expression-input component has these events:

load
change

It has these attributes:

fixed: if present the UI shows a text input
fixed-type: 'none' | 'text' | 'date' | 'email' | 'number' | 'password' | 'tel' | 'time' | 'url' = 'text'
allow-fixed: shows the buttons to switch from expression to fixed
placeholder
for: Form id. This is the same API as input elements
reactive: if present, when the user changes the selection of a select, then all the selects after it will be removed. This feels like data is a tree.

It has these properties:

value: the concatenation of all select' values. This is readonly.
options: array of all selected <option>
dirty

It has these slots:

placeholder
dirty-icon
fixed: you can use it to control the text input. Add an <inout> or a <textarea> into it
default: contains the select elements

Development / contribution

Setup

Install dependencies:

npm i

Build

This sample uses the TypeScript compiler to produce JavaScript that runs in modern browsers.

To build the JavaScript version of your component:

npm run build

To watch files and rebuild when the files are modified, run the following command in a separate shell:

npm run build:watch

Both the TypeScript compiler and lit-analyzer are configured to be very strict. You may want to change tsconfig.json to make them less strict.

Testing

This sample uses modern-web.dev's @web/test-runner for testing. See the modern-web.dev testing documentation for more information.

Tests can be run with the test script, which will run your tests against Lit's development mode (with more verbose errors) as well as against Lit's production mode:

npm test

For local testing during development, the test:dev:watch command will run your tests in Lit's development mode (with verbose errors) on every change to your source files:

npm test:watch

Alternatively the test:prod and test:prod:watch commands will run your tests in Lit's production mode.

Dev Server

This sample uses modern-web.dev's @web/dev-server for previewing the project without additional build steps. Web Dev Server handles resolving Node-style "bare" import specifiers, which aren't supported in browsers. It also automatically transpiles JavaScript and adds polyfills to support older browsers. See modern-web.dev's Web Dev Server documentation for more information.

To run the dev server and open the project in a new browser tab:

npm run serve

There is a development HTML file located at /dev/index.html that you can view at http://localhost:8000/dev/index.html. Note that this command will serve your code using Lit's development mode (with more verbose errors). To serve your code against Lit's production mode, use npm run serve:prod.

Editing

If you use VS Code, we highly recommend the lit-plugin extension, which enables some extremely useful features for lit-html templates:

Syntax highlighting
Type-checking
Code completion
Hover-over docs
Jump to definition
Linting
Quick Fixes

The project is setup to recommend lit-plugin to VS Code users if they don't already have it installed.

Linting

Linting of TypeScript files is provided by ESLint and TypeScript ESLint. In addition, lit-analyzer is used to type-check and lint lit-html templates with the same engine and rules as lit-plugin.

The rules are mostly the recommended rules from each project, but some have been turned off to make LitElement usage easier. The recommended rules are pretty strict, so you may want to relax them by editing .eslintrc.json and tsconfig.json.

To lint the project run:

npm run lint

Formatting

Prettier is used for code formatting. It has been pre-configured according to the Lit's style. You can change this in .prettierrc.json.

Prettier has not been configured to run when committing files, but this can be added with Husky and pretty-quick. See the prettier.io site for instructions.

Static Site

This project includes a simple website generated with the eleventy static site generator and the templates and pages in /docs-src. The site is generated to /docs and intended to be checked in so that GitHub pages can serve the site from /docs on the master branch.

To enable the site go to the GitHub settings and change the GitHub Pages "Source" setting to "master branch /docs folder".

To build the site, run:

npm run docs

To serve the site locally, run:

npm run docs:serve

To watch the site files, and re-build automatically, run:

npm run docs:watch

The site will usually be served at http://localhost:8000.

Note: The project uses Rollup to bundle and minify the source code for the docs site and not to publish to NPM. For bundling and minification, check the Bundling and minification section.

Bundling and minification

As stated in the static site generation section, the bundling and minification setup in the Rollup configuration in this project is there specifically for the docs generation.

We recommend publishing components as unoptimized JavaScript modules and performing build-time optimizations at the application level. This gives build tools the best chance to deduplicate code, remove dead code, and so on.

Please check the Publishing best practices for information on publishing reusable Web Components, and Build for production for building application projects that include LitElement components, on the Lit site.

More information

See Get started on the Lit site for more information.