在const内部定义函数

Question

I typed the code below in react-native and it returned the following error

undefined is not a function (evaluating 'this.createPiece('T')')

I don't know how to define it. Please help me

    const player = {
    pos: {x: 5, y: 5},
    matrix: this.createPiece('T'),
};

and the createPiece method:

createPiece(type) {
    if (type == 'T') {
        return [
            [0, 0, 0],
            [1, 1, 1],
            [0, 1, 0],
        ];
    }
}

full code

Answer 1

Try this :

  this.createPiece = function (type) {
        if (type== 'T') {
            return [
                [0, 0, 0],
                [1, 1, 1],
                [0, 1, 0],
            ];
        }
    };
    const player = {
        pos: {x: 5, y: 5},
        matrix: this.createPiece('T'),
    };

Answer 2

I figured out the answer:

• React Native:

Just use state instead of const

• React:

Just use const , it more global