watches/dist/index.mjs

import fs, { readdirSync, statSync } from 'fs';
import { promisify } from 'util';
import path, { resolve, join } from 'path';

/* es-module-lexer 0.3.26 */
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init=WebAssembly.compile((E="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","function"==typeof atob?Uint8Array.from(atob(E),A=>A.charCodeAt(0)):Buffer.from(E,"base64"))).then(WebAssembly.instantiate).then(({exports:A})=>{B=A;});var E;

function totalist(dir, callback, pre='') {
	dir = resolve('.', dir);
	let arr = readdirSync(dir);
	let i=0, abs, stats;
	for (; i < arr.length; i++) {
		abs = join(dir, arr[i]);
		stats = statSync(abs);
		stats.isDirectory()
			? totalist(abs, callback, join(pre, arr[i]))
			: callback(join(pre, arr[i]), abs, stats);
	}
}

var chokidar = require('chokidar');
require = require("esm")(module);


const readFile = promisify(fs.readFile);

function isHidden(p, ignore, only){
  // Ignore only if ignore is set and ignore test passes
  let shouldIgnore = ignore && ignore.test(p);
  // if only isn't set, include everything. Otherwise, must pass only test
  let shouldInclude = !only || only.test(p);
  // file is hidden if it shouldn't be included OR it should be ignored
  return !shouldInclude || shouldIgnore
}

const cwdify = (p) => path.join(process.cwd(),p.replace(process.cwd(), ''));

async function file_info(p){
  await init;
  let js = (path.extname(p) === '.js');
  let module = js ? require(p) : void 0;
  let contents = await readFile(p);
  let [imports, exports] = js ? parse(contents.toString('utf8')) : [null,null];
  return { imports, exports, contents, js, p, module }
}

class Watcher{
  constructor(sources, options={}){
    Object.assign(this, {
      sources: (Array.isArray(sources) ? sources : [sources]).map(s => cwdify(path.normalize(s))),
      options,
      targets: {},
      dependents: {},
      subscribers: {}
    });
    this.cache = options.cache;
    this.updateDependents = this.updateDependents.bind(this);
    this.effects = this.effects.bind(this);
    this.changeFile = this.changeFile.bind(this);
    this.init = this.init.bind(this);
    this.remove = this.remove.bind(this);
    this.format = this.format.bind(this);

    this.watcher = chokidar.watch(this.sources, {
      ...options.chokidar,
      ignoreInitial: true
    })
    .on('add', this.changeFile)
    .on('change', this.changeFile)
    .on('unlink', this.remove)
    .on('unlinkDir', this.remove);

    this.init().then(() => {
      this.dispatch('ready', this.format(Object.keys(this.targets)));
    }).catch(e => {
      this.dispatch('error', "Error initializing watches");
      console.log(e);
    });
  }

  format(arr=[]){
    return arr.map(p => {
      let info = this.targets[p];
      return {
        contents: info.contents,
        module: info.module,
        p
      }
    })
  }

  async changeFile(p){
    try{
      p = cwdify(p);
      await this.updateDependents(p);
      let changed = await this.effects(p);
      if(changed.length > 0){
        this.dispatch('change', this.format(changed), this.format(Object.keys(this.targets)));
      }
    } catch(e){
      this.dispatch('error', e);
    }
  }

  async remove(p){
    try {
      p = cwdify(p);
      let removed = [];
      Object.keys(this.dependents).forEach(k => {
        this.dependents[k].forEach(dep => {
          if(dep.startsWith(p)){
            this.dependents[k].delete(dep);
            removed.push(dep);
          }
        });
        if(this.dependents[k].size === 0 || k.startsWith(p)){
          delete this.dependents[k];
        }
      });
      this.dispatch('remove', removed);
    } catch(e){
      this.dispatch('error', e);
    }
  }

  isTarget(p){
    return this.sources.some(s => p.startsWith(s)) && !isHidden(p, this.options.ignore, this.options.only)
  }

  async init(){
    await init;
    let targets = await scan(this.sources, this.options);
    await Promise.all(
      targets.map(({p}) => this.updateDependents(p))
    );
  }

  clearCache(p){
    if(this.cache){
      delete this.cache[p];
    }
    delete require.cache[p];
  }


  async effects(p,changed=new Set()){
    // if in source directory and isn't hidden
    if(this.isTarget(p)){
      changed.add(p);
    }
    this.clearCache(p);
    if(this.dependents[p]){
      let effect = async function(dep){
        await this.effects(dep,changed);
      }.bind(this);
      let promises = [];
      this.dependents[p].forEach((dep) => {
        promises.push(effect(dep));
      });
      await Promise.all(promises);
    }
    return [...changed.values()];
  }

  async updateDependents(p){
    this.clearCache(p);
    let info = await file_info(p);
    if(this.isTarget(p)){
      this.targets[p] = info;
      this.watcher.add(p);
    }
    if(info.js){
      let relevant_imports = info.imports
        // get import string
        .map(({s,e}) => info.contents.toString('utf8').substring(s,e))
        // only include local imports
        .filter(str => str.startsWith('.'))
        // ensure import string includes .js extension
        .map(str => str.endsWith('.js') ? str : str + '.js') 
        // resolve import path
        .map(str => path.join(path.dirname(p), str));

      await Promise.all(
        relevant_imports.map(async import_path => {
          // if we haven't already tracked this file
          if(!this.dependents[import_path]){
            this.dependents[import_path] = new Set([p]);
            // recursively search for dependencies to trigger file changes
            await this.updateDependents(import_path);
            // watch dependency for file changes
            this.watcher.add(import_path);
          }
          else {
            // ensure this path is included in dependency's dependents
            this.dependents[import_path].add(p);
          }
        })
      );
    }
    
  }

  async dispatch(event, ...args){
    if(this.subscribers[event]){
      let promises = [];
      this.subscribers[event].forEach(cb => promises.push(cb(...args)));
      await Promise.all(promises);
    }
  }

  on(event, callback){
    if(this.subscribers[event]){
      this.subscribers[event].add(callback);
    } else {
      this.subscribers[event] = new Set([callback]);
    }
    return this;
  }
  
}

function watch(source, cache, options){
  return new Watcher(source, cache, options);
}

async function scan(sources=[], options={}){
  let targets = [];
  sources = (Array.isArray(sources) ? sources : [sources]).map(path.normalize);

  sources.forEach(src => {
    if(fs.lstatSync(src).isDirectory()){
      totalist(src,  (rel) => {
        let p = cwdify(path.join(src,rel));
        if(!isHidden(p, options.ignore, options.only)){
          targets.push(file_info(p));
        }
      });
    } else {
      let p = cwdify(src);
      targets.push(file_info(p));
    }
  });
  
  return await Promise.all(targets)
}

export { scan, watch };