A work in progress to make a Babel plugin that compiles VerbalExpression (nice library to create RegEx) into proper RegEx's at compile time

VerExBabelPlugin.js

import VerEx from 'verbal-expressions';

const eventualCallIs = name => {
  // FOR PERF
  const boundCheck = node =>
    node.type === 'Identifier' && node.name === name ||
    node.type === 'MemberExpression' && boundCheck(node.object) ||
    node.type === 'CallExpression' && boundCheck(node.callee)

  return boundCheck;
};

const allLiteral = (soFar, obj) => soFar && Boolean(obj.type.match(/Literal$/))
const literal = node =>
    node.type === 'Identifier'
  ||
    node.type === 'CallExpression' &&
    node.arguments.reduce(allLiteral, true) &&
    literal(node.callee)
  ||
    node.type === 'MemberExpression' &&
    node.property.type === 'Identifier' &&
    node.object.type === 'CallExpression' &&
    literal(node.object)



const chainToArray = (node) =>
  node.type === 'CallExpression' ?
    [...chainToArray(node.callee), node.arguments.map(arg => arg.value)]
  : node.type === 'MemberExpression' ?
    [...chainToArray(node.object), ...chainToArray(node.property)]
  : node.type === 'Identifier' ?
    [node.name]
  :
    [];

const chainFn = (obj, [methodName, args, ...rest]) =>
  rest.length ? 
    chainFn(obj[methodName](...args), rest) 
  : obj[methodName](...args);
  

export default function ({types: t}) {
  return {
    visitor: {
      CallExpression(path) {
        if( path.parent.type !== 'MemberExpression'
         && eventualCallIs('VerEx')(path.node.callee)
         && literal(path.node)
        ){
            var x = chainToArray(path.node);
            if(x[0] === 'VerEx' && Array.isArray(x[1]) && x[1].length === 0) {
              let veo = chainFn(VerEx(), x.slice(2));	
              path.replaceWithSourceString(veo.toString());
            }
        }
      }
    }
  };
}

...And it's done. Seems to work right.

Current limitations:

• You can't just chain the regex methods after the creating the regEx.
• Currently impossible to use VerEx chain as an argument in another VerEx Chain.

So this will not work:

var tester2 =
    VerEx()
    .startOfLine()
    .then(
      VerEx()
      .then('http')
      .maybe('s')
      .or()
      .then('ftp')
    )
    .then('://')
    .maybe('www.')
    .anythingBut(' ')
    .endOfLine()

http://astexplorer.net/#/TiJfAVumDf/1

Interesting. Why not spawn a repo?