File Explorer

1const fs = require('fs/promises')2const { runInThisContext } = require('vm')3const { promisify } = require('util')4const { randomBytes } = require('crypto')5const { Module } = require('module')6const { dirname, basename } = require('path')7const { read } = require('read')8 9const files = {}10 11class PromZard {12  #file = null13  #backupFile = null14  #ctx = null15  #unique = randomBytes(8).toString('hex')16  #prompts = []17 18  constructor (file, ctx = {}, options = {}) {19    this.#file = file20    this.#ctx = ctx21    this.#backupFile = options.backupFile22  }23 24  static async promzard (file, ctx, options) {25    const pz = new PromZard(file, ctx, options)26    return pz.load()27  }28 29  static async fromBuffer (buf, ctx, options) {30    let filename = 031    do {32      filename = '\0' + Math.random()33    } while (files[filename])34    files[filename] = buf35    const ret = await PromZard.promzard(filename, ctx, options)36    delete files[filename]37    return ret38  }39 40  async load () {41    if (files[this.#file]) {42      return this.#loaded()43    }44 45    try {46      files[this.#file] = await fs.readFile(this.#file, 'utf8')47    } catch (er) {48      if (er && this.#backupFile) {49        this.#file = this.#backupFile50        this.#backupFile = null51        return this.load()52      }53      throw er54    }55 56    return this.#loaded()57  }58 59  async #loaded () {60    const mod = new Module(this.#file, module)61    mod.loaded = true62    mod.filename = this.#file63    mod.id = this.#file64    mod.paths = Module._nodeModulePaths(dirname(this.#file))65 66    this.#ctx.prompt = this.#makePrompt()67    this.#ctx.__filename = this.#file68    this.#ctx.__dirname = dirname(this.#file)69    this.#ctx.__basename = basename(this.#file)70    this.#ctx.module = mod71    this.#ctx.require = (p) => mod.require(p)72    this.#ctx.require.resolve = (p) => Module._resolveFilename(p, mod)73    this.#ctx.exports = mod.exports74 75    const body = `(function(${Object.keys(this.#ctx).join(', ')}) { ${files[this.#file]}\n })`76    runInThisContext(body, this.#file).apply(this.#ctx, Object.values(this.#ctx))77    this.#ctx.res = mod.exports78 79    return this.#walk()80  }81 82  #makePrompt () {83    return (...args) => {84      let p, d, t85      for (let i = 0; i < args.length; i++) {86        const a = args[i]87        if (typeof a === 'string') {88          if (p) {89            d = a90          } else {91            p = a92          }93        } else if (typeof a === 'function') {94          t = a95        } else if (a && typeof a === 'object') {96          p = a.prompt || p97          d = a.default || d98          t = a.transform || t99        }100      }101      try {102        return `${this.#unique}-${this.#prompts.length}`103      } finally {104        this.#prompts.push([p, d, t])105      }106    }107  }108 109  async #walk (o = this.#ctx.res) {110    const keys = Object.keys(o)111 112    const len = keys.length113    let i = 0114 115    while (i < len) {116      const k = keys[i]117      const v = o[k]118      i++119 120      if (v && typeof v === 'object') {121        o[k] = await this.#walk(v)122        continue123      }124 125      if (v && typeof v === 'string' && v.startsWith(this.#unique)) {126        const n = +v.slice(this.#unique.length + 1)127 128        // default to the key129        // default to the ctx value, if there is one130        const [prompt = k, def = this.#ctx[k], tx] = this.#prompts[n]131 132        try {133          o[k] = await this.#prompt(prompt, def, tx)134        } catch (er) {135          if (er.notValid) {136            // eslint-disable-next-line no-console137            console.log(er.message)138            i--139          } else {140            throw er141          }142        }143        continue144      }145 146      if (typeof v === 'function') {147        // XXX: remove v.length check to remove cb from functions148        // would be a breaking change for `npm init`149        // XXX: if cb is no longer an argument then this.#ctx should150        // be passed in to allow arrow fns to be used and still access ctx151        const fn = v.length ? promisify(v) : v152        o[k] = await fn.call(this.#ctx)153        // back up so that we process this one again.154        // this is because it might return a prompt() call in the cb.155        i--156        continue157      }158    }159 160    return o161  }162 163  async #prompt (prompt, def, tx) {164    const res = await read({ prompt: prompt + ':', default: def }).then((r) => tx ? tx(r) : r)165    // XXX: remove this to require throwing an error instead of166    // returning it. would be a breaking change for `npm init`167    if (res instanceof Error && res.notValid) {168      throw res169    }170    return res171  }172}173 174module.exports = PromZard.promzard175module.exports.fromBuffer = PromZard.fromBuffer176module.exports.PromZard = PromZard177