error TS2554: Expected 0-1 arguments, but got 2-CodePudding

I don't get why the compiler five me such an error message.
I am trying to insert a lambda as an argument to a function and thereby get an error. Thanks in advance to all the helpers!

const allOperationSymbols = [' ', '-', '/', '*', '^'] as const;
export type OperationSymbol = typeof allOperationSymbols[number];

type OperationMap = Map<OperationSymbol, (Left: Value, Right: Value) => Value>;

export class Type {

    private definedOperations: Set<OperationMap>;

     public appendOperation(operationMap: OperationMap) {
        this.definedOperations.add(operationMap);
    }
}

class Types {
    private value: Array<Type> = [];

    public appendType(type: Type) {
        this.value.push(type);
    }

    public addInteger() {
        let Integer: Type;
        Integer = new Type('Integer', new Set());

        const operationMap = new Map(' ', /*here is the error*/ (Left: Value, Right: Value): Value => {
        const LeftNumber = Number(Left);
        const RightNumber = Number(Right);
        const areIntegers = Number.isInteger(LeftNumber) && Number.isInteger(RightNumber);
        if (LeftNumber != NaN && RightNumber != NaN && areIntegers) {
            return new Value((Number(Left)   Number(Right)).toString(), Integer);
        }
    });

    Integer.appendOperation(operationMap);

    this.appendType(Integer);
    }
}

CodePudding user response：

Expected 0-1 arguments, but got 2

You are using the Map constructor wrong (and TypeScript is pointing it out).

Your usage:

new Map(' ', function);

The Map constructor in JavaScript takes nothing (0 arguments) or an array (1 argument) of key,value tuples. e.g. correct usage (1 argument version):

 new Map([
   [' ', function]
 ]);

See : https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/Map

CodePudding user response：

There are a several issues with your code.

private definedOperations: Set<OperationMap>; - has not initializer.

Possible fix: private definedOperations: Set<OperationMap> = new Set()

Type class does not expects any constructor argument, whereas you are trying to pass two: 'Integer' and new Set() here new Type('Integer', new Set());
Map expects one iterable argument, like here: new Map([['key','value']]). It means that if you want to create new instance of Map with some initial key/value pair, you should do it like here:

     const operationMap: OperationMap = new Map([[' ', (Left: Value, Right: Value): Value => {
            const LeftNumber = Number(Left);
            const RightNumber = Number(Right);
            const areIntegers = Number.isInteger(LeftNumber) && Number.isInteger(RightNumber);
            if (LeftNumber != NaN && RightNumber != NaN && areIntegers) {
                return new Value((Number(Left)   Number(Right)).toString(), Integer);
            }
            return new Value('default', Integer)
        }]]);

And the last one, (Left: Value, Right: Value): Value should always return a Value, whereas you are trying to return Value conditionaly. If your data does not meet this reuirements LeftNumber != NaN && RightNumber != NaN && areIntegers you should return some default Value.

Working code without errors:

const allOperationSymbols = [' ', '-', '/', '*', '^'] as const;
export type OperationSymbol = typeof allOperationSymbols[number];

class Value {
    constructor(arg: string, type: Type) { }
}

type OperationMap = Map<OperationSymbol, (Left: Value, Right: Value) => Value>;

export class Type {

    private definedOperations: Set<OperationMap> = new Set()

    public appendOperation(operationMap: OperationMap) {
        this.definedOperations.add(operationMap);
    }
    constructor(type: string, set: Set<unknown>) { }
}

class Types {
    private value: Array<Type> = [];

    public appendType(type: Type) {
        this.value.push(type);
    }

    public addInteger() {
        let Integer: Type;
        Integer = new Type('Integer', new Set());

        const operationMap: OperationMap = new Map([[' ', (Left: Value, Right: Value): Value => {
            const LeftNumber = Number(Left);
            const RightNumber = Number(Right);
            const areIntegers = Number.isInteger(LeftNumber) && Number.isInteger(RightNumber);
            if (LeftNumber != NaN && RightNumber != NaN && areIntegers) {
                return new Value((Number(Left)   Number(Right)).toString(), Integer);
            }
            return new Value('default', Integer)
        }]]);

        Integer.appendOperation(operationMap);

        this.appendType(Integer);
    }
}

Playground

P.S. Try to use Number.isNan instead of RightNumber != NaN. It is much safer. See docs

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