Promise Me helps you move your code from using callbacks to using promises, for example through Q, RSVP.js or when.js.
It parses your code and then manipulates the AST to transform the callbacks into calls to then(), including a rejection handler if you handle the original callback error. Think of it as a slightly smarter find-and-replace. It will probably break your code and require you to fix it.
Try the live demo!
$ npm install -g promise-me
$ promise-me script.jsvar promiseMe = require("promise-me");
var before = "...";
var after = promiseMe.convert(before, options);Convert the given code to use promises.
{string} codeString containing Javascript code.{Object} optionsOptions for generation.{Object} options.parseOptions foresprima.parse. See http://esprima.org/doc/ .{Object} options.generateOptions forescodegen.generate. See https://github.com/Constellation/escodegen/wiki/API .{Function} options.matcherA function of form(node) => boolean. Must accept any type of node and return true if it should be transformed intothen, using the replacer, and false if not. See https://developer.mozilla.org/en-US/docs/SpiderMonkey/Parser_API for node types.{Function} options.replacerA function of form(node) => Node. Must accept any type of node and return a new node to replace it that usestheninstead of a callback. Will only get called if options.matcher returns true. See https://developer.mozilla.org/en-US/docs/SpiderMonkey/Parser_API for node types.{Function} options.flattenerA function of form(node) => Node. Must accept any type of node, and return either return the original node, or a new node with thethencalls flattened.{Function} logFunction to call with log messages.- Returns
{string}The Javascript code with callbacks replaced with.then()functions.
Before:
getDetails("Bob", function (err, details) {
console.log(details)
});After:
getDetails('Bob').then(function (details) {
console.log(details);
});Before:
getDetails("Bob", function (err, details) {
if (err) {
console.error(err);
return;
}
console.log(details)
});After:
getDetails('Bob').then(function (details) {
console.log(details);
}, function (err) {
console.error(err);
return;
});Before:
getDetails("Bob", function (err, details) {
getLongLat(details.address, details.country, function(err, longLat) {
getNearbyBars(longLat, function(err, bars) {
console.log("Your nearest bar is: " + bars[0]);
});
});
});After:
getDetails('Bob').then(function (details) {
return getLongLat(details.address, details.country);
}).then(function (longLat) {
return getNearbyBars(longLat);
}).then(function (bars) {
console.log('Your nearest bar is: ' + bars[0]);
});Before:
getDetails("Bob", function (err, details) {
getLongLat(details.address, details.country, function(err, longLat) {
getNearbyBars(longLat, function(err, bars) {
// Note the captured `details` variable
console.log("The closest bar to " + details.address + " is: " + bars[0]);
});
});
});After:
getDetails("Bob").then(function (details) {
getLongLat(details.address, details.country).then(function (longLat) {
return getNearbyBars(longLat);
}).then(function (bars) {
// Note the captured `details` variable
console.log("The closest bar to " + details.address + " is: " + bars[0]);
});
});
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