Tag Archives: code of the day

Code of the Day: Javascript Date.prototype.setDay()

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In Javascript, I find it strange how `Date.prototype.getDay()` in defined but `Date.prototype.setDay()`.
So here’s the code for `Date.prototype.setDay()`.

// Sets the Date object to the day of the week.
// @param {Number} - dayIndex must be from 0 - 6, where 0 is sunday.
// @return {Number} returns the primitive value of the Date object.
Date.prototype.setDay = Date.prototype.setDay || function (dayIndex) {
	dayIndex = Math.floor(+dayIndex);
	if (dayIndex < 0 || 6 < dayIndex) {
		throw new Error("Must pass integer between 0-6, where sunday is 0.");
	}
	this.setDate( this.getDate() + dayIndex - this.getDay() );
	return this.valueOf();
};

Demo 1

var a = new Date(Date.parse("Feb 1, 2014"));
a.setDay(0);
console.log(a.toDateString() === "Sun Jan 26 2014" );
a.setDay(6);
console.log(a.toDateString() === "Sat Feb 01 2014" );

Demo 2

// Prings the Monday - Friday for the current day.
var getWeekString = function () {
	var days = [],
		date = new Date();
 
	for (var i = 1, len = 6; i < len; i++) {
		date.setDay(i)
		days.push("## " + date.toDateString() );
	}
	return days;
};
console.log(getWeekString().join("\n\n"));

If you looking for a good Javascript Date library, checkout moment.js.

More info:
MDN Date Object

Larry Battle

I love to program, and discover new tech. Check out my stackoverflow and github accounts.

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Code of the day: Javascript Flatten()

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/**
* Returns an array that contains non-array elements.
* If an element is an array, then the element is replaced by the content of the array.
* @param{Array} 
* @return{Array} return null if no arguments are passed.
* @example 
    flatten([[1,2],3,[4]]); // returns [1,2,3,4];
*/
var flatten = function(arr){
	if(!Array.isArray(arr)){
		return (arr === null || arr === undefined) ? null : [arr];
	}
	var result = [], obj;
	for(var i = 0, len = arr.length; i < len; i++){
		obj = arr[i];
		if(Array.isArray(arr)){
			obj = flatten(obj);
		}
		result = result.concat( obj );
	}
    return result;
};

Larry Battle

I love to program, and discover new tech. Check out my stackoverflow and github accounts.

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Code of the Day: Coffeescript + jQuery, enforce max length for all input elements

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Enforce max length in all browsers since some browsers, IE8, don’t support maxlength for all input elements.

Coffeescript

# requires jQuery 1.6+ 
enforceMaxLength = ->
  $("[maxlength]").on "blur", ->
    $(@).val (index,val) -> 
      val.substring 0, $(@).attr("maxlength")

enforceMaxLength()

Javascript

// Generated by CoffeeScript 1.6.1
(function() {
  var enforceMaxLength;
 
  enforceMaxLength = function() {
    return $("[maxlength]").on("blur", function() {
      return $(this).val(function(index, val) {
        return val.substring(0, $(this).attr("maxlength"));
      });
    });
  };
 
  enforceMaxLength();
 
}).call(this);

Larry Battle

I love to program, and discover new tech. Check out my stackoverflow and github accounts.

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Code of the day: Javascript check if an object is empty

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`isObjectEmpty()` is a function that will only return true if the passed an object that contains no keys.
This is different than jQuery.isEmptyObject() because the passed argument MUST be an object.

/**
* Check to see if an object has any keys.
* @param {Object} obj
* @return {Boolean}
* @author Larry Battle <bateru.com/news>
* @license WTFPL
**/
var isObjectEmpty = function( obj ) {
	var name;
	for ( name in obj ) {
		return false;
	}
	return obj != null && typeof obj === "object";
};

Larry Battle

I love to program, and discover new tech. Check out my stackoverflow and github accounts.

More Posts - Website

Follow Me:
TwitterLinkedInYouTube