@@ -436,3 +436,97 @@ export const storageAvailable = (type: "localStorage" | "sessionStorage") => {
436436 return false ;
437437 }
438438} ;
439+
440+ // smaller implementation of lodash's isEqual from https://github.com/NickGard/tiny-isequal but made a bit more performant and typesafe
441+ const toString = Object . prototype . toString ,
442+ getPrototypeOf = Object . getPrototypeOf ,
443+ getOwnProperties = Object . getOwnPropertySymbols
444+ ? ( c : any ) => ( Object . keys ( c ) as any [ ] ) . concat ( Object . getOwnPropertySymbols ( c ) )
445+ : Object . keys ;
446+
447+ const checkEquality = ( a : any , b : any , refs : any [ ] ) : boolean => {
448+ // trivial case: primitives and referentially equal objects
449+ if ( a === b ) return true ;
450+
451+ // if both are null/undefined, the above check would have returned true
452+ if ( a == null || b == null ) return false ;
453+
454+ // check to see if we've seen this reference before; if yes, return true
455+ // eslint-disable-next-line lodash/prefer-includes
456+ if ( refs . indexOf ( a ) > - 1 && refs . indexOf ( b ) > - 1 ) return true ;
457+
458+ const aType = toString . call ( a ) ;
459+ const bType = toString . call ( b ) ;
460+
461+ let aElements , bElements , element ;
462+
463+ // save results for circular checks
464+ refs . push ( a , b ) ;
465+
466+ if ( aType != bType ) return false ; // not the same type of objects
467+
468+ // for non-null objects, check all custom properties
469+ aElements = getOwnProperties ( a ) ;
470+ bElements = getOwnProperties ( b ) ;
471+ if (
472+ aElements . length != bElements . length ||
473+ aElements . some ( function ( key ) {
474+ return ! checkEquality ( a [ key ] , b [ key ] , refs ) ;
475+ } )
476+ ) {
477+ return false ;
478+ }
479+
480+ switch ( aType . slice ( 8 , - 1 ) ) {
481+ case "Symbol" :
482+ return a . valueOf ( ) == b . valueOf ( ) ;
483+ case "Date" :
484+ case "Number" :
485+ return + a == + b || ( + a != + a && + b != + b ) ; // convert Dates to ms, check for NaN
486+ case "RegExp" :
487+ case "Function" :
488+ case "String" :
489+ case "Boolean" :
490+ return "" + a == "" + b ;
491+ case "Set" :
492+ case "Map" : {
493+ aElements = a . entries ( ) ;
494+ bElements = b . entries ( ) ;
495+ do {
496+ element = aElements . next ( ) ;
497+ if ( ! checkEquality ( element . value , bElements . next ( ) . value , refs ) ) {
498+ return false ;
499+ }
500+ } while ( ! element . done ) ;
501+ return true ;
502+ }
503+ case "ArrayBuffer" :
504+ ( a = new Uint8Array ( a ) ) , ( b = new Uint8Array ( b ) ) ; // fall through to be handled as an Array
505+ case "DataView" :
506+ ( a = new Uint8Array ( a . buffer ) ) , ( b = new Uint8Array ( b . buffer ) ) ; // fall through to be handled as an Array
507+ case "Float32Array" :
508+ case "Float64Array" :
509+ case "Int8Array" :
510+ case "Int16Array" :
511+ case "Int32Array" :
512+ case "Uint8Array" :
513+ case "Uint16Array" :
514+ case "Uint32Array" :
515+ case "Uint8ClampedArray" :
516+ case "Arguments" :
517+ case "Array" :
518+ if ( a . length != b . length ) return false ;
519+ for ( element = 0 ; element < a . length ; element ++ ) {
520+ if ( ! ( element in a ) && ! ( element in b ) ) continue ; // empty slots are equal
521+ // either one slot is empty but not both OR the elements are not equal
522+ if ( element in a != element in b || ! checkEquality ( a [ element ] , b [ element ] , refs ) ) return false ;
523+ }
524+ return true ;
525+ case "Object" :
526+ return checkEquality ( getPrototypeOf ( a ) , getPrototypeOf ( b ) , refs ) ;
527+ default :
528+ return false ;
529+ }
530+ } ;
531+
532+ export const isEqual = ( a : any , b : any ) => checkEquality ( a , b , [ ] ) ;
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