Node js custom minifier for the Cre8bitJS library.

cre8bit-minifier.js

const events = require('events')
const fs = require('fs')
const readline = require('readline')
const a2z = ['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z']
const fileName = process.argv[2]
const varMin = [...a2z.slice(0, 13)]
const constMin = [...a2z.slice(0, 23)]
const letMin = [...a2z.slice(0, 10)]
const funcMin = [...a2z.slice(0, 7)]
const spacesAround = ['=', , '===', '=>', '+', '&&', '?', '>', '+=']
const spaceAfter = ['if', ':', ',']
const spaceBefore = ['(', '{', ':', '`']
const varNames = {}
let newData = '';

const processLineByLine = async () => {
    try {
        const rl = readline.createInterface({
            input: fs.createReadStream(`../${fileName}.js`),
            crlfDelay: Infinity
        })

        for await (let line of rl) {
            for (const varName in varNames) {
                // Replace #private & scoped vars and methods with short identifier
                line.includes(varName) && (line = line.replace(new RegExp(varName, 'g'), varNames[varName]))
            }

            line = line.replace(/^\s+/, '')

            // Remove unnecessary spaces only
            if (!line.startsWith('/') && !line.startsWith('*')) {
                for (const char of spacesAround) {
                    line = line.replace(` ${char} `, char)
                }
                for (const char of spaceAfter) {
                    line = line.replace(`${char} `, char)
                }
                for (const char of spaceBefore) {
                    line = line.replace(` ${char}`, char)
                }

                newData += line
            }
        }
        // Remove occurrences of ; before } and ' * ' once all code is on one line
        newData = newData.replaceAll(/\s\*\s/g, '*');
        newData = newData.replaceAll(/;}/g, '}')

        fs.writeFile(`../${fileName}.min.js`, newData, () => console.log('Minification complete'))
        await events.once(rl, 'close')

      } catch (err) {
        console.error(err)
      }
}

const getVars = async () => {
    try {
        const rl = readline.createInterface({
            input: fs.createReadStream(`../${fileName}.js`),
            crlfDelay: Infinity
        })

        let varInc = 0
        let constInc = 0
        let funcInc = 0
        let letInc = 0
        for await (let line of rl) {
            line = line.replace(/^\s+/, '')
            if (line.startsWith('#') && !line.includes('(')) {
                const varName = line.split(' ')
                varNames[varName[0]] = `#${varMin[varInc]}V`

                varInc++
            } else if (line.startsWith('const ')) {
                const varName = line.match(/(?<=\s)(.*?)(?=\s)/)
                varNames[varName[0]] = `${constMin[constInc]}C`

                constInc++
            }  else if (line.startsWith('#') && line.includes('(')) {
                const varName = line.split('(')
                varNames[varName[0]] = `#${funcMin[funcInc]}F`

                funcInc++
            } else if (line.startsWith('let ')) {
                const varName = line.match(/(?<=\s)(.*?)(?=\s)/)
                varNames[varName[0]] = `${letMin[letInc]}L`

                letInc++
            }
        }

        processLineByLine()
      } catch (err) {
        console.error(err)
      }
}

getVars()