Extracting Typescript Exports To Json File Using Gulp

I have several typescript files, some of them export a certain var - named APIS - which is an array of objects. I want to extract the values of all of these exports, and pipe them

Solution 1:

The typescript compiler API is relevant here, as this is what you need to parse and understand the ts-code properly. Unfortunately, I don't think there is a gulp plugin that implements this API.

I think your best bet is to change strategy completely here and solve your problem in another way, or to use regex to try to extract the constants that you want. Unless you want to write your own gulp-plugin using the compiler API.

Solution 2:

This is what I ended up doing, and it worked for me. I'm positing it here in case anyone else finds it useful. :)

Instead of .ts, I saved the exports in .js files, i.e:

service2.export.js:

exports.APIS = [ { "field2" : "yadayada" }, { "field3" : "yadabla" } ];

Based on the answer given here: https://stackoverflow.com/a/36869651/3007732 I created a gulp task as following:

var gulp = require('gulp');
var concat = require('gulp-concat');
var map = require('gulp-map');
var fs = require('fs');

var allServices;

gulp.task('default', function() {

    var allServices = [];

    var stream = gulp.src('./**/*.export.js')
        .pipe(map(function(file) {
            var obj = require(file.path);
            if (obj.APIS != null) {
                allServices.push.apply(allServices, obj.APIS);
            }
            return file;
        }));

    stream.on("end", function (cb)
    {   
        fs.writeFile('./export.json', JSON.stringify(allServices), cb);
    });

    return stream;
});

and now I get the following output in export.json:

[ { "field1" : "blabla" }, { "field2" : "yadayada" }, { "field3" : "yadabla" } ]

which is exactly what I wanted.