/*!
* VisualEditor Object freeze utilities.
*
* @copyright See AUTHORS.txt
*/
( function () {
const freezeProxyHandler = {
set: ( obj, name ) => {
throw new Error( 'Object is frozen, can\'t set property: ' + name );
},
deleteProperty: ( obj, name ) => {
throw new Error( 'Object is frozen, can\'t delete property: ' + name );
}
};
if ( !window.Proxy || !window.Set ) {
return;
}
let deepFreeze;
/**
* Deep freeze an object, making it immutable
*
* Original object properties are overwritten with frozen versions.
*
* @param {Object} object Object to freeze
* @param {boolean} [onlyProperties] Only freeze properties (or array items)
* @param {Set} [seen] Set of already-seen objects (for internal, recursive use)
* @return {Object} Immutable deep copy of the original object
*/
ve.deepFreeze = deepFreeze = function ( object, onlyProperties, seen ) {
if ( !seen ) {
seen = new Set();
seen.add( object );
}
for ( const name in object ) {
if ( Object.prototype.hasOwnProperty.call( object, name ) ) {
const value = object[ name ];
if (
// Truth check so we don't try to freeze null
value &&
typeof value === 'object' &&
!seen.has( value ) &&
!Object.isFrozen( value )
) {
seen.add( value );
// Recurse. Use local name (tests may alias ve.deepFreeze)
object[ name ] = deepFreeze( value, false, seen );
}
}
}
if ( !onlyProperties ) {
object = new window.Proxy( object, freezeProxyHandler );
// Object#freeze isn't really necessary after proxying,
// but use it so we can detect frozen objects with Object.isFrozen.
Object.freeze( object );
}
return object;
};
}() );