snappymail/vendors/underscore/underscore.custom.js

//     Underscore.js 1.9.2
//     https://underscorejs.org
//     (c) 2009-2018 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
//     Underscore may be freely distributed under the MIT license.
/*
_.debounce
_.defer
_.throttle
*/

(() => {

  // Baseline setup
  // --------------

  // Create a safe reference to the Underscore object for use below.
  var _ = function(obj) {
    if (obj instanceof _) return obj;
    if (!(this instanceof _)) return new _(obj);
  };

  // Export the Underscore object for **Node.js**, with
  // backwards-compatibility for their old module API. If we're in
  // the browser, add `_` as a global object.
  // (`nodeType` is checked to ensure that `module`
  // and `exports` are not HTML elements.)
  if (typeof exports != 'undefined' && !exports.nodeType) {
    if (typeof module != 'undefined' && !module.nodeType && module.exports) {
      exports = module.exports = _;
    }
    exports._ = _;
  } else {
    // Establish the root object, `window` (`self`) in the browser, `global`
    // on the server, or `this` in some virtual machines. We use `self`
    // instead of `window` for `WebWorker` support.
    var root = typeof self == 'object' && self.self === self && self ||
            typeof global == 'object' && global.global === global && global ||
            this ||
            {};
    root._ = _;
  }

  // Current version.
  _.VERSION = '1.9.2';

  // An internal function for creating a new object that inherits from another.
  var baseCreate = function(prototype) {
    if (typeof prototype !== 'object') return {};
    return Object.create(prototype);
  };

  // Function (ahem) Functions
  // ------------------

  // Determines whether to execute a function as a constructor
  // or a normal function with the provided arguments.
  var executeBound = function(sourceFunc, boundFunc, context, callingContext, args) {
    if (!(callingContext instanceof boundFunc)) return sourceFunc.apply(context, args);
    var self = baseCreate(sourceFunc.prototype);
    var result = sourceFunc.apply(self, args);
    return (typeof result === 'object') ? result : self;
  };

  // Defers a function, scheduling it to run after the current call stack has
  // cleared.
  _.defer = (() => {
	var func = (func, wait, ...args) => setTimeout(() => func.apply(null, args), wait);
    var bound = function(...params) {
      var position = 0;
      var args = [params[position++], 1];
      while (position < params.length) args.push(params[position++]);
      return executeBound(func, bound, this, this, args);
    };
    return bound;
  })();

  // Returns a function, that, when invoked, will only be triggered at most once
  // during a given window of time. Normally, the throttled function will run
  // as much as it can, without ever going more than once per `wait` duration;
  // but if you'd like to disable the execution on the leading edge, pass
  // `{leading: false}`. To disable execution on the trailing edge, ditto.
  _.throttle = function(func, wait, options) {
    var timeout, context, args, result;
    var previous = 0;
    if (!options) options = {};

    var later = function() {
      previous = options.leading === false ? 0 : Date.now();
      timeout = null;
      result = func.apply(context, args);
      if (!timeout) context = args = null;
    };

    var throttled = function() {
      var now = Date.now();
      if (!previous && options.leading === false) previous = now;
      var remaining = wait - (now - previous);
      context = this;
      args = arguments;
      if (remaining <= 0 || remaining > wait) {
        if (timeout) {
          clearTimeout(timeout);
          timeout = null;
        }
        previous = now;
        result = func.apply(context, args);
        if (!timeout) context = args = null;
      } else if (!timeout && options.trailing !== false) {
        timeout = setTimeout(later, remaining);
      }
      return result;
    };

    throttled.cancel = function() {
      clearTimeout(timeout);
      previous = 0;
      timeout = context = args = null;
    };

    return throttled;
  };

  // Returns a function, that, as long as it continues to be invoked, will not
  // be triggered. The function will be called after it stops being called for
  // N milliseconds. If `immediate` is passed, trigger the function on the
  // leading edge, instead of the trailing.
  _.debounce = function(func, wait, immediate) {
    var timeout, result;

    var later = function(context, args) {
      timeout = null;
      if (args) result = func.apply(context, args);
    };

    var debounced = function(...args) {
      if (timeout) clearTimeout(timeout);
      if (immediate) {
        var callNow = !timeout;
        timeout = setTimeout(later, wait);
        if (callNow) result = func.apply(this, args);
      } else {
        var obj = this;
        timeout = setTimeout(() => later.apply(null, [obj, args]), wait);
      }

      return result;
    };

    debounced.cancel = function() {
      clearTimeout(timeout);
      timeout = null;
    };

    return debounced;
  };

  // AMD registration happens at the end for compatibility with AMD loaders
  // that may not enforce next-turn semantics on modules. Even though general
  // practice for AMD registration is to be anonymous, underscore registers
  // as a named module because, like jQuery, it is a base library that is
  // popular enough to be bundled in a third party lib, but not be part of
  // an AMD load request. Those cases could generate an error when an
  // anonymous define() is called outside of a loader request.
  if (typeof define == 'function' && define.amd) {
    define('underscore', [], function() {
      return _;
    });
  }
})();