src/core/init.js

   1 // Initialize a jQuery object
   2 import { jQuery } from "../core.js";
   3 import { document } from "../var/document.js";
   4 import { rsingleTag } from "./var/rsingleTag.js";
   5 import { isObviousHtml } from "./isObviousHtml.js";
   6
   7 import "../traversing/findFilter.js";
   8
   9 // A central reference to the root jQuery(document)
  10 var rootjQuery,
  11
  12         // A simple way to check for HTML strings
  13         // Prioritize #id over <tag> to avoid XSS via location.hash (trac-9521)
  14         // Strict HTML recognition (trac-11290: must start with <)
  15         // Shortcut simple #id case for speed
  16         rquickExpr = /^(?:\s*(<[\w\W]+>)[^>]*|#([\w-]+))$/,
  17
  18         init = jQuery.fn.init = function( selector, context ) {
  19                 var match, elem;
  20
  21                 // HANDLE: $(""), $(null), $(undefined), $(false)
  22                 if ( !selector ) {
  23                         return this;
  24                 }
  25
  26                 // HANDLE: $(DOMElement)
  27                 if ( selector.nodeType ) {
  28                         this[ 0 ] = selector;
  29                         this.length = 1;
  30                         return this;
  31
  32                 // HANDLE: $(function)
  33                 // Shortcut for document ready
  34                 } else if ( typeof selector === "function" ) {
  35                         return rootjQuery.ready !== undefined ?
  36                                 rootjQuery.ready( selector ) :
  37
  38                                 // Execute immediately if ready is not present
  39                                 selector( jQuery );
  40
  41                 } else {
  42
  43                         // Handle obvious HTML strings
  44                         match = selector + "";
  45                         if ( isObviousHtml( match ) ) {
  46
  47                                 // Assume that strings that start and end with <> are HTML and skip
  48                                 // the regex check. This also handles browser-supported HTML wrappers
  49                                 // like TrustedHTML.
  50                                 match = [ null, selector, null ];
  51
  52                         // Handle HTML strings or selectors
  53                         } else if ( typeof selector === "string" ) {
  54                                 match = rquickExpr.exec( selector );
  55                         } else {
  56                                 return jQuery.makeArray( selector, this );
  57                         }
  58
  59                         // Match html or make sure no context is specified for #id
  60                         // Note: match[1] may be a string or a TrustedHTML wrapper
  61                         if ( match && ( match[ 1 ] || !context ) ) {
  62
  63                                 // HANDLE: $(html) -> $(array)
  64                                 if ( match[ 1 ] ) {
  65                                         context = context instanceof jQuery ? context[ 0 ] : context;
  66
  67                                         // Option to run scripts is true for back-compat
  68                                         // Intentionally let the error be thrown if parseHTML is not present
  69                                         jQuery.merge( this, jQuery.parseHTML(
  70                                                 match[ 1 ],
  71                                                 context && context.nodeType ? context.ownerDocument || context : document,
  72                                                 true
  73                                         ) );
  74
  75                                         // HANDLE: $(html, props)
  76                                         if ( rsingleTag.test( match[ 1 ] ) && jQuery.isPlainObject( context ) ) {
  77                                                 for ( match in context ) {
  78
  79                                                         // Properties of context are called as methods if possible
  80                                                         if ( typeof this[ match ] === "function" ) {
  81                                                                 this[ match ]( context[ match ] );
  82
  83                                                         // ...and otherwise set as attributes
  84                                                         } else {
  85                                                                 this.attr( match, context[ match ] );
  86                                                         }
  87                                                 }
  88                                         }
  89
  90                                         return this;
  91
  92                                 // HANDLE: $(#id)
  93                                 } else {
  94                                         elem = document.getElementById( match[ 2 ] );
  95
  96                                         if ( elem ) {
  97
  98                                                 // Inject the element directly into the jQuery object
  99                                                 this[ 0 ] = elem;
 100                                                 this.length = 1;
 101                                         }
 102                                         return this;
 103                                 }
 104
 105                         // HANDLE: $(expr) & $(expr, $(...))
 106                         } else if ( !context || context.jquery ) {
 107                                 return ( context || rootjQuery ).find( selector );
 108
 109                         // HANDLE: $(expr, context)
 110                         // (which is just equivalent to: $(context).find(expr)
 111                         } else {
 112                                 return this.constructor( context ).find( selector );
 113                         }
 114                 }
 115
 116         };
 117
 118 // Give the init function the jQuery prototype for later instantiation
 119 init.prototype = jQuery.fn;
 120
 121 // Initialize central reference
 122 rootjQuery = jQuery( document );