JavaScript Template Literal Handler

An educational project to practise JavaScript template literal handling with a tag function.

Installation
Development
- The task
  - Level 1 template handling developer
  - Level 80 template handling developer
Project improvement and bug reporting

Installation

The project requires NodeJS v.14+ and npm installed.

Fork the project and clone it locally.

Run npm i to install required dependencies.

Development

Check the requirements below and implement the features as requested.

You will add your implementation in ./src/transform.js

Run npm test to see if your implementation meets requirements.

Your code will be prettified and linted on commit. If linter reports code style errors then fix them. Fill free linting your code with npm run lint at any time during the development.

The task

Implement transform function that being applied to a template will return a string where every expression in a template is transformed following the as set below in the levels' description.

You will also need to implement testFunction to test function expression transformation.

Each level offers a skill up.

Level 1 template handling developer

transform function should transform expressions per their types:

number - multiplied by 2 and incremented by 3 (e.g. 5 becomes 13)
string - all lowercase. (e.g. a RED fox! cunning,SliCk and Quick. becomes a red fox! cunning,slick and quick.)
function - specified function gets called and is expected to return its own name, all caps
object - a JSON representation of a simple object (no need to handle circular references, Symbols, or functions as properties)
anything else - let JS handle it

Implement testFunction that expects no parameters and returns its own name, all caps.

You may want to employ the following:

String.prototype.toLowerCase.
JSON methods to implement objects transformation.

Feel free implementing any other helper functions that transform and/or testFunction would use, as required.

transform`a = ${5}`;
// 'a = 13'

transform`Let me tell you about ${'a RED fox! cunning,SliCk and quick.'} The end`;
// 'Let me tell you about a red fox! cunning,slick and quick. The end'

transform`a = ${{ b: 5, c: 'def' }}`;
// 'a = {"b":5,"c":"def"}'

transform`a = ${testFunction}`;
// 'a = TESTFUNCTION'

transform`a = ${testFunction} value ${5}`;
// 'a = TESTFUNCTION value 13'

transform`Let me tell you about ${'a RED fox! cunning,SliCk and quick.'} The end.
  ${{ b: 5, c: 'def' }}
  a = ${testFunction} value Z ${5}`;
// 'Let me tell you about a red fox! cunning,slick and quick. The end.
//   {"b":5,"c":"def"}
//   a = TESTFUNCTION value Z 13'

Level 80 template handling developer

Change level variable value as appropriate.

Implement transform function as per requirements above with the changes as follows.

Function testFunction should expect two parameters and return its own name, all caps, and next string fragment (whitespaces removed) and next expression glued with '=', parenthesized.

NB! Next expression should be exposed as is, without any transformations applied.

See examples below.

You may want to employ:

String.prototype.replace to transform strings. Make sure you use g flag for a matching RegExp.

NB! String.prototype.replaceAll may not be supported by your/latest version of NodeJS.

Examples:

transform`a${5} = ${testFunction} value Z ${5}`;
// 'a = TESTFUNCTION(valueZ=5)'

transform`Let me tell you about ${'a RED fox! cunning,SliCk and quick.'} The end.
  ${{ b: 5, c: 'def' }}
  a${5} = ${testFunction} value Z ${5}`;
// 'Let me tell you about a red fox! cunning,slick and quick. The end.
//   {"b":5,"c":"def"}
//   a13 = TESTFUNCTION(valueZ=5)'

Project improvement and bug reporting

Found a bug in documentation or code? Please report it via issues.

Feel free opening PRs to fix issues or otherwise improve the project.

Please note that this project doesn't accept pull requests with task implementation code.

mustbefail/js-template-literal-handler