Source File
	builtin_symbol.go

Belonging Package
	github.com/dop251/goja

package goja

import "github.com/dop251/goja/unistring"

var (
	SymHasInstance        = newSymbol(asciiString("Symbol.hasInstance"))
	SymIsConcatSpreadable = newSymbol(asciiString("Symbol.isConcatSpreadable"))
	SymIterator           = newSymbol(asciiString("Symbol.iterator"))
	SymMatch              = newSymbol(asciiString("Symbol.match"))
	SymMatchAll           = newSymbol(asciiString("Symbol.matchAll"))
	SymReplace            = newSymbol(asciiString("Symbol.replace"))
	SymSearch             = newSymbol(asciiString("Symbol.search"))
	SymSpecies            = newSymbol(asciiString("Symbol.species"))
	SymSplit              = newSymbol(asciiString("Symbol.split"))
	SymToPrimitive        = newSymbol(asciiString("Symbol.toPrimitive"))
	SymToStringTag        = newSymbol(asciiString("Symbol.toStringTag"))
	SymUnscopables        = newSymbol(asciiString("Symbol.unscopables"))
)

func (r *Runtime) builtin_symbol(call FunctionCall) Value {
	var desc String
	if arg := call.Argument(0); !IsUndefined(arg) {
		desc = arg.toString()
	}
	return newSymbol(desc)
}

func (r *Runtime) symbolproto_tostring(call FunctionCall) Value {
	sym, ok := call.This.(*Symbol)
	if !ok {
		if obj, ok := call.This.(*Object); ok {
			if v, ok := obj.self.(*primitiveValueObject); ok {
				if sym1, ok := v.pValue.(*Symbol); ok {
					sym = sym1
				}
			}
		}
	}
	if sym == nil {
		panic(r.NewTypeError("Method Symbol.prototype.toString is called on incompatible receiver"))
	}
	return sym.descriptiveString()
}

func (r *Runtime) symbolproto_valueOf(call FunctionCall) Value {
	_, ok := call.This.(*Symbol)
	if ok {
		return call.This
	}

	if obj, ok := call.This.(*Object); ok {
		if v, ok := obj.self.(*primitiveValueObject); ok {
			if sym, ok := v.pValue.(*Symbol); ok {
				return sym
			}
		}
	}

	panic(r.NewTypeError("Symbol.prototype.valueOf requires that 'this' be a Symbol"))
}

func (r *Runtime) symbol_for(call FunctionCall) Value {
	key := call.Argument(0).toString()
	keyStr := key.string()
	if v := r.symbolRegistry[keyStr]; v != nil {
		return v
	}
	if r.symbolRegistry == nil {
		r.symbolRegistry = make(map[unistring.String]*Symbol)
	}
	v := newSymbol(key)
	r.symbolRegistry[keyStr] = v
	return v
}

func (r *Runtime) symbol_keyfor(call FunctionCall) Value {
	arg := call.Argument(0)
	sym, ok := arg.(*Symbol)
	if !ok {
		panic(r.NewTypeError("%s is not a symbol", arg.String()))
	}
	for key, s := range r.symbolRegistry {
		if s == sym {
			return stringValueFromRaw(key)
		}
	}
	return _undefined
}

func (r *Runtime) thisSymbolValue(v Value) *Symbol {
	if sym, ok := v.(*Symbol); ok {
		return sym
	}
	if obj, ok := v.(*Object); ok {
		if pVal, ok := obj.self.(*primitiveValueObject); ok {
			if sym, ok := pVal.pValue.(*Symbol); ok {
				return sym
			}
		}
	}
	panic(r.NewTypeError("Value is not a Symbol"))
}

func (r *Runtime) createSymbolProto(val *Object) objectImpl {
	o := &baseObject{
		class:      classObject,
		val:        val,
		extensible: true,
		prototype:  r.global.ObjectPrototype,
	}
	o.init()

	o._putProp("constructor", r.getSymbol(), true, false, true)
	o.setOwnStr("description", &valueProperty{
		configurable: true,
		getterFunc: r.newNativeFunc(func(call FunctionCall) Value {
			return r.thisSymbolValue(call.This).desc
		}, "get description", 0),
		accessor: true,
	}, false)
	o._putProp("toString", r.newNativeFunc(r.symbolproto_tostring, "toString", 0), true, false, true)
	o._putProp("valueOf", r.newNativeFunc(r.symbolproto_valueOf, "valueOf", 0), true, false, true)
	o._putSym(SymToPrimitive, valueProp(r.newNativeFunc(r.symbolproto_valueOf, "[Symbol.toPrimitive]", 1), false, false, true))
	o._putSym(SymToStringTag, valueProp(newStringValue("Symbol"), false, false, true))

	return o
}

func (r *Runtime) createSymbol(val *Object) objectImpl {
	o := r.newNativeFuncAndConstruct(val, r.builtin_symbol, func(args []Value, newTarget *Object) *Object {
		panic(r.NewTypeError("Symbol is not a constructor"))
	}, r.getSymbolPrototype(), "Symbol", _positiveZero)

	o._putProp("for", r.newNativeFunc(r.symbol_for, "for", 1), true, false, true)
	o._putProp("keyFor", r.newNativeFunc(r.symbol_keyfor, "keyFor", 1), true, false, true)

	for _, s := range []*Symbol{
		SymHasInstance,
		SymIsConcatSpreadable,
		SymIterator,
		SymMatch,
		SymMatchAll,
		SymReplace,
		SymSearch,
		SymSpecies,
		SymSplit,
		SymToPrimitive,
		SymToStringTag,
		SymUnscopables,
	} {
		n := s.desc.(asciiString)
		n = n[len("Symbol."):]
		o._putProp(unistring.String(n), s, false, false, false)
	}

	return o
}

func (r *Runtime) getSymbolPrototype() *Object {
	ret := r.global.SymbolPrototype
	if ret == nil {
		ret = &Object{runtime: r}
		r.global.SymbolPrototype = ret
		ret.self = r.createSymbolProto(ret)
	}
	return ret
}

func (r *Runtime) getSymbol() *Object {
	ret := r.global.Symbol
	if ret == nil {
		ret = &Object{runtime: r}
		r.global.Symbol = ret
		ret.self = r.createSymbol(ret)
	}
	return ret
}

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