@hishprorg/quis-doloribus NPM

@hishprorg/quis-doloribus

@hishprorg/quis-doloribus is a lighter-weight, more narrowly focused package that aims to accomplish some of the goals of regenerator, while remaining small enough that it won’t (completely) break a website’s performance budget if run in the browser. It may not be able to boast as impressive size reductions as preact has compared to react, but it is a quarter of the size of regenerator (minified and gzipped), while supporting most of the same features.

This library does not aim to support the full set of ES6 to ES5 transforms. Specifically, it supports:

destructuring assignment
block scoping (let and const) to var
arrow functions
async / await
generators (sync and async)
for ... of loops
function parameter destructuring
function parameter defaults
rest / spread syntax
simple template literals
shorthand object properties
computed object properties

It intentionally does not (and will not) support transforms for:

classes
import / export
react, jsx, flow, or typescript syntax
tagged template literals

API

@hishprorg/quis-doloribus.compile

This function accepts a javascript string and returns ES5-compatible javascript. If generators are involved, it assumes regeneratorRuntime is available in the global scope.

// input
import { compile } from '@hishprorg/quis-doloribus';

console.log(compile('function *gen() { yield 1; }'));

// output
var _marked = /* #__PURE__ */ regeneratorRuntime.mark(gen);
function gen() {
  return regeneratorRuntime.wrap(function gen$(_context) {
    while (1) switch (_context.prev = _context.next) {
      case 0:
        _context.next = 2;
        return 1;
      case 2:
      case "end":
        return _context.stop();
    }
  }, _marked);
}

@hishprorg/quis-doloribus.transform

Also importable from @@hishprorg/quis-doloribus/transform; performs an AST transform (conforming to the ESTree Spec) to ES5-compatible AST.

import transform from '@@hishprorg/quis-doloribus/transform';

// input: AST for `let {x} = y`
var ast = transform({
  type: 'File',
  program: {
    type: 'Program',
    body: [{
      type: 'VariableDeclaration',
      kind: 'let',
      declarations: [{
        type: 'VariableDeclarator',
        id: {
          type: 'ObjectPattern',
          properties: [
            {
              type: 'ObjectProperty',
              key: {type: 'Identifier', name: 'x'},
              value: {type: 'Identifier', name: 'x'},
              shorthand: true
            }
          ]
        },
        init: {type: 'Identifier', name: 'y'}
      }]
    }]
  }
});
console.log(ast);

// result: AST for `var _y = y; var x = _y.x`
{
  type: 'File',
  program: {
    type: 'Program',
    body: [{
      type: 'VariableDeclaration',
      kind: 'var',
      declarations: [{
        type: 'VariableDeclarator',
        id:   {type: 'Identifier', name: '_y'},
        init: {type: 'Identifier', name: 'y'}
      }]
    }, {
      type: 'VariableDeclaration',
      kind: 'var',
      declarations: [{
        type: 'VariableDeclarator',
        id: {type: 'Identifier', name: 'x'},
        init: {
          type: 'MemberExpression',
          object:   {type: 'Identifier', name: '_y'},
          property: {type: 'Identifier', name: 'x'},
          computed: false
        }
      }]
    }]
  }
}