javascript - Matching and writing data between 2 directories with node.js -

so i'll try , make sound simple possible, because don't understand im doing.

basically have 2 directories, sake of example call them 'a' , 'b'. 'a' directory other directories inside of it(inside files). 'b' directory itself, files in it, contain data.

i need match files , b, , write data b a.

this example code, not best because im extremely confused, tried make simple possible read

var id = [] function match(){     var = fs.readdirsync(__dirname+"/x/")     var b = fs.readdirsync(__dirname+"/y/")     id.push(a)     for(o in id){         fs.readdirsync(__dirname+"/x/"+id[o])         // got confused, heres example         if(file names in id[o] match b){             write data b, id[o]         }     } } match() 

edit: aside moving files, need copy files. directory have files a,b,c. , directory b have a,b,d. , b being copied, , file d being left alone.

posit labs suggestion of a duplicate question in comments wise if want done. top rated answer suggests package ncp.

assuming you're in learn, however...

the objective function that

1. takes source directory , target directory
2. enumerates contents
3. copies files source target
4. makes source directories in target , recursively calls on each directory pair

be aware: solution very demo , should not used in production. use of recursion bite if file system deep, fact code synchronous (*sync) can slow down.

instead of string building paths, use path module. handles cross platform , strange inputs , edge cases.

first, 2 helper functions: ensuring directories exist should , copying file 1 path another. ultimately, these 2 real tasks in mirroring 2 directories.

var ensuredirectoryexists = function(path) {     if (fs.existssync(path)) return;     fs.mkdirsync(path); }  var copyfile = function(sourcefile, targetfile) {     if (fs.existssync(targetfile)) return;     fs.writefilesync(targetfile, fs.readfilesync(sourcefile)); } 

then main work. ensure directories exist , read contents.

ensuredirectoryexists(source); ensuredirectoryexists(target); var sourcelist = fs.readdirsync(source); var targetlist = fs.readdirsync(target); 

then every element in source directory

sourcelist.foreach(function(sourcefile) { /* code */ }) 

quickly check if exists (just name. real work, should check types , checksum)

if (targetlist.indexof(sourcefile) > -1) return; 

gather information on target (fs.stats detailed in manual)

var fullsourcepath = path.join(source, sourcefile); var fulltargetpath = path.join(target, sourcefile); var filestats = fs.statsync(fullsourcepath); 

last, perform correct action based on type. files copied, directories ensured exist , recursively called, , else causes program shrug , keep going.

if (filestats.isfile()) {     copyfile(fullsourcepath, fulltargetpath); } else if (filestats.isdirectory()) {     copydirectories(fullsourcepath, fulltargetpath); } else {     // there can other things in list. see https://nodejs.org/api/fs.html#fs_class_fs_stats     console.log(`not sure ${sourcefile} is. ignoring.`); } 

complete solution

var fs = require('fs'); var path = require('path');  var ensuredirectoryexists = function(path) {     if (fs.existssync(path)) return;     fs.mkdirsync(path); }  var copyfile = function(sourcefile, targetfile) {     // console.log(`copying ${sourcefile} ${targetfile}`);     if (fs.existssync(targetfile)) return;     fs.writefilesync(targetfile, fs.readfilesync(sourcefile));      // or streams. note ignores errors. read more here: https://stackoverflow.com/questions/11293857/fastest-way-to-copy-file-in-node-js     // fs.createreadstream(sourcefile).pipe(fs.createwritestream(targetfile)); }  var copydirectories = function(source, target) {     // console.log(`copying ${source} ${target}`);      // ensure directories exist     ensuredirectoryexists(source);     ensuredirectoryexists(target);     var sourcelist = fs.readdirsync(source);     var targetlist = fs.readdirsync(target);      //sourcelist has contents of directories     sourcelist.foreach(function(sourcefile) {         // omit file it exists         // note quite naive, work demo purposes         if (targetlist.indexof(sourcefile) > -1) return;          var fullsourcepath = path.join(source, sourcefile);         var fulltargetpath = path.join(target, sourcefile);         var filestats = fs.statsync(fullsourcepath);         // console.log(`${sourcefile} ${filestats.isfile() ? 'file' : (filestats.isdirectory() ? 'directory' : '??')}.`);          if (filestats.isfile()) {             copyfile(fullsourcepath, fulltargetpath);         } else if (filestats.isdirectory()) {             copydirectories(fullsourcepath, fulltargetpath);         } else {             // there can other things in list. see https://nodejs.org/api/fs.html#fs_class_fs_stats             console.log(`not sure ${sourcefile} is. ignoring.`);         }     }); }  copydirectories(     path.join(__dirname, 'source'),     path.join(__dirname, 'target') )