Using Q.js in Node.js to implement promise of API

Here we look at how to implement the node API promise with Q.js.

　　First, everything is install

The code is as follows:

NPM Install Q

　　Second, the standard node style API Promise method

　　1. Use Q.nfcall

Relative to Q.fcall, Q.nfcall is node's q.fcall.

The code is as follows:

var FS = require (' FS '),

Q = require (' Q '),

Colors = require (' colors '),

File = ' Example.txt ';

var fsreadfile = Q.nfcall (fs.readfile,file,encoding);

Fsreadfile.then (function (result) {

Console.log (("Invoke in Nfcall" + file). Red);

Console.log (Result.green);

},function (Error) {

Console.log ("Invoke in Nfcall". Red);

Console.log (Error.tostring (). Red);

}

);

　　2. Use Q.denodeify

The code is as follows:

var fsreadfile_denodeify = q.denodeify (fs.readfile);

Fsreadfile_denodeify (file,encoding). Then (function (Result) {

Console.log ("Invoke in Denodeify". Red);

Console.log (Result.green)

},function (Error) {

Console.log ("Invoke in Denodeify". Red);

Console.log (Error.tostring (). Red);

}

);

　　3. Use Q.deferd

The code is as follows:

var fsreadfile_deferd = function (file,encoding) {

var deferred = Q.defer ();

Fs.readfile (File,encoding,function (error,result) {

if (Error) {

Deferred.reject (Error.tostring (). Red);

}

Deferred.resolve (result);

});

return deferred.promise;

};

Fsreadfile_deferd (file). Then (function (Result) {

Console.log ("Invoke in Deferd". Red);

Console.log (Result.tostring (). Green);

},function (Error) {

Console.log ("Invoke in Deferd". Red);

Console.log (Error.tostring (). Red);

}

);

　　4. Use Makenoderesolver ()

The code is as follows:

var fsreadfile_makenoderesolver = function (file,encoding) {

var deferred = Q.defer ();

Fs.readfile (File,encoding,deferred.makenoderesolver ());

return deferred.promise;

};

Fsreadfile_makenoderesolver (file,encoding). Then (function (Result) {

Console.log ("Invoke in Makenoderesolver". Red);

Console.log (Result.green);

},function (Error) {

Console.log (Error.tostring (). Red);

});