How to use the cordova-lib.cordova.platforms function in cordova-lib

gulp.task("build-android", function () {
    cordova.platforms("add", "android");
    return gulp.src('dist')
        .pipe(cordova.clean("android"))
        .pipe(cordova.build("android", buildArgs));
});

gulp.task("build-ios", function () {
    cordova.platforms("add", "ios");
    return gulp.src('dist')
        .pipe(cordova.clean("ios"))
        .pipe(cordova.build("ios", buildArgs));
});

gulp.task("build-win", function () {
    cordova.platforms("add", "windows");
    return gulp.src('dist')
        .pipe(cordova.clean("windows"))
        .pipe(cordova.build("windows", buildArgs));
});