wait for things to settle before running a task

gulpfile.js

"use strict";

var gulp = require("gulp");
var exec = require("gulp-exec");
var _ = require("lodash");

// This task will do nothing until it hasn't been triggered within 1s.
gulp.task("exec", _.debounce(function () {
    return gulp.src(["..."], { read: false })
        .pipe(exec("ctags -R"));
}, 1000));

gulp.task("watch", function () {
    gulp.watch("...", ["exec"]);
});