Summary of JavaScript common string and array extension functions
- 2021-02-17 06:16:34
- OfStack
The extension function of the String object:
String.prototype.trim = function() {
return this.replace(/^\s+|\s+$/g,"");
}
String.prototype.ltrim = function() {
return this.replace(/^\s+/g,"");
}
String.prototype.rtrim = function() {
return this.replace(/\s+$/g,"");
}
String.prototype.splitAndTrim = function($delimiter, $limit)
{
var $ss = this.split($delimiter, $limit);
for(var $i=0; $i<$ss.length; $i++)
$ss[$i] = $ss[$i].trim();
return $ss;
}
String.prototype.htmlEntities = function () {
return this.replace(/&/g,'&').replace(/</g,'<').replace(/>/g,'>');
}
String.prototype.stripTags = function () {
return this.replace(/<([^>]+)>/g,'');
}
String.prototype.toArray = function() {
return this.split('');
}
String.prototype.toIntArray = function() {
var returnArray = [];
for (var i=0; i<this.length; i++) {
returnArray.push(this.charCodeAt(i));
}
return returnArray;
}
String.prototype.replaceAll = function($old, $snew){
return this.replace(new RegExp($old,"gm"),$snew);
}
Variable substitution
var a = "I Love {0}, and You Love {1},Where are {0}!";a.format("You","Me");
String.prototype.format = function(){
var args = arguments;
return this.replace(/\{(\d+)\}/g,function(m,i,o,n){
return args[i];
});
}
Appends a string to the end of a string
String.prototype.append = function($str){
return this.concat($str);
}
Deletes the character at the specified index position. Invalid index will not delete any characters
String.prototype.deleteCharAt = function($sIndex){
if($sIndex<0 || $sIndex>=this.length){
return this.valueOf();
}else if($sIndex==0){
return this.substring(1,this.length);
}else if($sIndex==this.length-1){
return this.substring(0,this.length-1);
}else{
return this.substring(0,$sIndex)+this.substring($sIndex+1);
}
}
Deletes the string between the specified indexes.$sIndex and $eIndex characters are not deleted! Rely on deleteCharAt
String.prototype.deleteString = function($sIndex, $eIndex){
if($sIndex==$eIndex){
return this.deleteCharAt($sIndex);
}else{
if($sIndex>$eIndex){
var tIndex=$eIndex;
$eIndex=$sIndex;
$sIndex=tIndex;
}
if($sIndex<0)$sIndex=0;
if($eIndex>this.length-1)$eIndex=this.length-1;
return this.substring(0,$sIndex+1)+this.substring($eIndex,this.length);
}
}
Check if the string ends with a string (str)
String.prototype.endsWith = function($str){
return this.substr(this.length - $str.length) == $str;
}
Checks if the string starts with a string
String.prototype.startsWith = function(str){
return this.substr(0, str.length) == str;
}
Compare two strings for equality, case insensitive!
String.prototype.equalsIgnoreCase = function($str){
if(this.length!=$str.length){
return false;
}else{
var tmp1=this.toLowerCase();
var tmp2=$str.toLowerCase();
return tmp1==tmp2;
}
}
Inserts the specified string after the specified position! Invalid indexes are appended directly to the end of the string
String.prototype.insert = function($ofset, $str){
if($ofset<0 || $ofset>=this.length-1){
return this.concat($str);
}
return this.substring(0,$ofset)+$str+this.substring($ofset+1);
}
Sets a character at the specified position to another specified character or string. Invalid index will be returned without any processing!
String.prototype.setCharAt = function($ofset, $str){
if($ofset<0 || $ofset>=this.length-1){
return this.valueOf();
}
return this.substring(0,$ofset)+$str+this.substring($ofset+1);
}
String.prototype.replaceLen = function(start, len, replaced) {
if(!len)
return this;
if(start >= this.length)
return this;
var returnSeg = '';
var returnSeg2 = '';
var i = 0;
for (; i < this.length; i++){
var c = this.charAt(i);
if(i < start)
returnSeg += c;
if(i >= start + len)
returnSeg2 += c;
}
return returnSeg + replaced + returnSeg2;
}
Extending base classes:
Replace characters. This is useful when filling in substitutions, such as *** day *** hour with
<
input /
>
day
<
input /
>
hours
var a = "I Love {0}, and You Love {1},Where are {0}!";a.format("You","Me");
String.prototype.format = function(){
var args = arguments;
return this.replace(/\{(\d+)\}/g,function(m,i,o,n){
return args[i];
});
}
0
Arrange the string in reverse order
String.prototype.reverse = function(){
var str="";
for(var i=this.length-1;i>=0;i--){
str=str.concat(this.charAt(i));
}
return str;
}
Calculate the length, two lengths for each Chinese character and one length for each English character
String.prototype.ucLength = function(){
var len = 0;
for(var i=0;i<this.length;i++){
if(this.charCodeAt(i)>255)len+=2;
else len++;
}
return len;
}
Fill the left side of the string with 1 of the specified characters
var a = "I Love {0}, and You Love {1},Where are {0}!";a.format("You","Me");
String.prototype.format = function(){
var args = arguments;
return this.replace(/\{(\d+)\}/g,function(m,i,o,n){
return args[i];
});
}
3
Piles 1 character to the right of the string
var a = "I Love {0}, and You Love {1},Where are {0}!";a.format("You","Me");
String.prototype.format = function(){
var args = arguments;
return this.replace(/\{(\d+)\}/g,function(m,i,o,n){
return args[i];
});
}
4
Converts the first letter of a string to uppercase
var a = "I Love {0}, and You Love {1},Where are {0}!";a.format("You","Me");
String.prototype.format = function(){
var args = arguments;
return this.replace(/\{(\d+)\}/g,function(m,i,o,n){
return args[i];
});
}
5
Converts a string formatted as 2008-04-02 10:08:44 to a date (the value of the String object must be 2008-04-02 10:08:44)
var a = "I Love {0}, and You Love {1},Where are {0}!";a.format("You","Me");
String.prototype.format = function(){
var args = arguments;
return this.replace(/\{(\d+)\}/g,function(m,i,o,n){
return args[i];
});
}
6
Converts a decimal number originally represented by a string to a decimal floating-point number: precision for precision
String.prototype.toFloat = function(precision){
precision = precision || 2;
return parseFloat(this,10).toFixed(precision);
}
Converts a decimal number originally represented as a string to a decimal integer
String.prototype.toInt = function(){
return parseInt(this,10).toString();
}
Returns as a string the sum of two decimal digits originally represented as a string: addend is the addend
var a = "I Love {0}, and You Love {1},Where are {0}!";a.format("You","Me");
String.prototype.format = function(){
var args = arguments;
return this.replace(/\{(\d+)\}/g,function(m,i,o,n){
return args[i];
});
}
9
10 to other base code as follows nextScale for base such as 2,8,16
String.prototype.shiftScale = function(nextScale){
return parseFloat(this).toString(nextScale);
}
Each base is converted to another:
The this object must be an integer
param preScale was originally a decimal number
@param nextScale to be converted to a decimal number
String.prototype.scaleShift = function(preScale,nextScale){
return parseInt(this,preScale).toString(nextScale);
}
document.write("ABC123, we are all good friends ");
String.prototype.dbc2sbc = function (){
return this.replace(/[\uff01-\uff5e]/g,function(a){return String.fromCharCode(a.charCodeAt(0)-65248);}).replace(/\u3000/g," ");
}
Array extension function:
var isNumeric = function(x) {
// returns true if x is numeric and false if it is not.
var RegExp = /^(-)?(\d*)(\.?)(\d*)$/;
return String(x).match(RegExp);
}
var myArray = [1,'two',3,'four',5,'six',7,'eight',9,'ten'];
var oddArray=myArray.filter(isNumeric); // outputs: 1,3,5,7,9
var oddArray=myArray.some(isNumeric); // outputs: true
var oddArray=myArray.every(isNumeric); // outputs: false
var printArray =function(x, idx){
document.writeln('['+idx+'] = '+x);
}
myArray.forEach(printArray);// outputs: [0] = 1 [1] = two [2] = 3 [3] = four [4] = 5
myArray.remove(9);
document.writeln(myArray);
if (!Array.prototype.every)
{
Array.prototype.every = function(fun /*, thisp*/)
{
var len = this.length;
if (typeof fun != "function")
throw new TypeError();
var thisp = arguments[1];
for (var i = 0; i < len; i++)
{
if (i in this &&
!fun.call(thisp, this[i], i, this))
return false;
}
return true;
};
}
if (!Array.prototype.filter)
{
Array.prototype.filter = function(fun /*, thisp*/)
{
var len = this.length;
if (typeof fun != "function")
throw new TypeError();
var res = new Array();
var thisp = arguments[1];
for (var i = 0; i < len; i++)
{
if (i in this)
{
var val = this[i]; // in case fun mutates this
if (fun.call(thisp, val, i, this))
res.push(val);
}
}
return res;
};
}
if (!Array.prototype.forEach)
{
Array.prototype.forEach = function(fun /*, thisp*/)
{
var len = this.length;
if (typeof fun != "function")
throw new TypeError();
var thisp = arguments[1];
for (var i = 0; i < len; i++)
{
if (i in this)
fun.call(thisp, this[i], i, this);
}
};
}
if (!Array.prototype.map)
{
Array.prototype.map = function(fun /*, thisp*/)
{
var len = this.length;
if (typeof fun != "function")
throw new TypeError();
var res = new Array(len);
var thisp = arguments[1];
for (var i = 0; i < len; i++)
{
if (i in this)
res[i] = fun.call(thisp, this[i], i, this);
}
return res;
};
}
if (!Array.prototype.some)
{
Array.prototype.some = function(fun /*, thisp*/)
{
var len = this.length;
if (typeof fun != "function")
throw new TypeError();
var thisp = arguments[1];
for (var i = 0; i < len; i++)
{
if (i in this &&
fun.call(thisp, this[i], i, this))
return true;
}
return false;
};
}
Array.prototype.sortNum = function() {
return this.sort( function (a,b) { return a-b; } );
}
<!--
var tmp = [5,9,12,18,56,1,10,42,'blue',30, 7,97,53,33,30,35,27,30,'35','Ball', 'bubble'];
var thirty=tmp.find(30); // Returns 9, 14, 17
var thirtyfive=tmp.find('35'); // Returns 18
var thirtyfive=tmp.find(35); // Returns 15
var haveBlue=tmp.find('blue'); // Returns 8
var notFound=tmp.find('not there!'); // Returns false
var regexp1=tmp.find(/^b/); // returns 8,20 (first letter starts with b)
var regexp1=tmp.find(/^b/i); // returns 8,19,20 (same as above but ignore case)
-->
Array.prototype.find = function(searchStr) {
var returnArray = false;
for (i=0; i<this.length; i++) {
if (typeof(searchStr) == 'function') {
if (searchStr.test(this[i])) {
if (!returnArray) { returnArray = [] }
returnArray.push(i);
}
} else {
if (this[i]===searchStr) {
if (!returnArray) { returnArray = [] }
returnArray.push(i);
}
}
}
return returnArray;
}
Randomly changes the sorting of arrays
Array.prototype.shuffle = function (){
for(var rnd, tmp, i=this.length; i; rnd=parseInt(Math.random()*i), tmp=this[--i], this[i]=this[rnd], this[rnd]=tmp);
return this;
}
<!--var myArray = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15];
var yourArray = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15];
document.writeln(myArray.compare(yourArray)); // outputs: true;-->
Array.prototype.compare = function(testArr) {
if (this.length != testArr.length) return false;
for (var i = 0; i < testArr.length; i++) {
if (this[i].compare) {
if (!this[i].compare(testArr[i])) return false;
}
if (this[i] !== testArr[i]) return false;
}
return true;
}
var a = new Array("5","7","7"); a.unique();
Array.prototype.unique = function() {
var data = this || [];
var a = {}; // The statement 1 An object, javascript Objects of the
for (var i = 0; i < data.length; i++) {
a[data[i]] = true; // Set the flag to the array value as the index, so that you can get rid of duplicate values
}
data.length = 0;
for (var i in a) { // Iterate through the object, restoring the marked ones to an array
this[data.length] = i;
}
return data;
}
Array.prototype.addAll = function($array)
{
if($array == null || $array.length == 0)
return;
for(var $i=0; $i<$array.length; $i++)
this.push($array[$i]);
}
Array.prototype.contains = function($value)
{
for(var $i=0; $i<this.length; $i++)
{
var $element = this[$i];
if($element == $value)
return true;
}
return false;
}
Array.prototype.indexOf = function($value)
{
for(var $i=0; $i<this.length; $i++)
{
if(this[$i] == $value)
return $i;
}
return -1;
}
if (!Array.prototype.lastIndexOf)
{
Array.prototype.lastIndexOf = function(elt /*, from*/)
{
var len = this.length;
var from = Number(arguments[1]);
if (isNaN(from))
{
from = len - 1;
}
else
{
from = (from < 0)
? Math.ceil(from)
: Math.floor(from);
if (from < 0)
from += len;
else if (from >= len)
from = len - 1;
}
for (; from > -1; from--)
{
if (from in this &&
this[from] === elt)
return from;
}
return -1;
};
}
Array.prototype.insertAt = function($value, $index)
{
if($index < 0)
this.unshift($value);
else if($index >= this.length)
this.push($value);
else
this.splice($index, 0, $value);
}
Deletes elements based on the index of an array
Array.prototype.removeByIndex=function($n) {
if($n<0){ // if n<0 , nothing is done.
return this;
}else{
return this.slice(0,$n).concat(this.slice($n+1,this.length));
}
}
Rely on indexOf
Array.prototype.remove = function($value)
{
var $index = this.indexOf($value);
if($index != -1)
this.splice($index, 1);
}
Array.prototype.removeAll = function()
{
while(this.length > 0)
this.pop();
}
Array.prototype.replace = function($oldValue, $newValue)
{
for(var $i=0; $i<this.length; $i++)
{
if(this[$i] == $oldValue)
{
this[$i] = $newValue;
return;
}
}
}
Array.prototype.swap = function($a, $b)
{
if($a == $b)
return;
var $tmp = this[$a];
this[$a] = this[$b];
this[$b] = $tmp;
}
Array.prototype.max = function() {
return Math.max.apply({}, this);
}
Array.prototype.min = function() {
return Math.min.apply({}, this);
}
Array.prototype.splice = function(start, delLen, item){
var len =this.length;
start = start<0?0:start>len?len:start?start:0;
delLen=delLen<0?0:delLen>len?len:delLen?delLen:len;
var arr =[],res=[];
var iarr=0,ires=0,i=0;
for(i=0;i<len;i++){
if(i<start|| ires>=delLen) arr[iarr++]=this[i];
else {
res[ires++]=this[i];
if(item&&ires==delLen){
arr[iarr++]=item;
}
}
}
if(item&&ires<delLen) arr[iarr]=item;
for(var i=0;i<arr.length;i++){
this[i]=arr[i];
}
this.length=arr.length;
return res;
}
Array.prototype.shift = function(){ if(!this) return[];return this.splice(0,1)[0];}
Add it separately, shallow, copy, and if you encounter an array, copy the elements of the array
Array.prototype.concat = function(){
var i=0;
while(i<arguments.length){
if(typeof arguments[i] === 'object'&&typeof arguments[i].splice ==='function' &&!arguments[i].propertyIsEnumerable('length')){
// NOT SHALLOW COPY BELOW
// Array.prototype.concat.apply(this,arguments[i++]);
var j=0;
while(j<arguments[i].length) this.splice(this.length,0,arguments[i][j++]);
i++;
} else{
this[this.length]=arguments[i++];
}
}
return this;
}
Array.prototype.join = function(separator){
var i=0,str="";
while(i<this.length) str+=this[i++]+separator;
return str;
}
Array.prototype.pop = function() { return this.splice(this.length-1,1)[0];}
Array.prototype.push = function(){
Array.prototype.splice.apply(this,
[this.length,0].concat(Array.prototype.slice.apply(arguments))); // Instead of processing the parameters directly, they are copied 1 Under the
return this.length;
}
Array.prototype.reverse = function(){
for(var i=0;i<this.length/2;i++){
var temp = this[i];
this[i]= this[this.length-1-i];
this[this.length-1-i] = temp;
}
return this;
}
Array.prototype.slice = function(start, end){
var len =this.length;
start=start<0?start+=len:start?start:0;
end =end<0?end+=len:end>len?len:end?end:len;
var i=start;
var res = [];
while(i<end){
res.push(this[i++]);
}
return res;
}
//arr.unshift(ele1,ele2,ele3....)
Array.prototype.unshift =function(){
Array.prototype.splice.apply(this,[0,0].concat(Array.prototype.slice.apply(this,arguments)));
}