如何在函数中将变量值作为参数传递

Question

I wasnted to know if it was possible to do something along the lines of:

var test = function(testValue){
    if(testValue == true) doThing1();
    if(testValue == false) doThing2();
}

The context of what this is for, I'm obviously new to JS and am creating a small game similar to an agario-but-simpler and I'm using it for movement. My ideal setup is:

class Player {
            /*
             * @param {int} x - x position
             * @param {int} y - y position
             * @param {int} size - size of object
             * 
             */
            constructor(x, y, size) {
                this.x = x;
                this.y = y;
                this.size = size;
                this.points = 0;
                this.velocity = 1;
                this.color = 'white';
                
            }

            addPoints(amount) {
                points += amount;
            }
 
            changeVelocity(newVelocity) {
                velocity = newVelocity;
            }

            moveLeft = function (canMove) {
                if (canMove) { this.x -= this.velocity; }
            }
            moveRight = function (canMove) {
                if (canMove) { this.x += this.velocity; }
            }
            moveUp = function (canMove) {
                if (canMove) { this.y -= this.velocity; }
            }
            moveDown = function (canMove) {
                if (canMove) { this.y += this.velocity; }
            }
        }

I'm looking to have keyDown 'w' set moveUp to true and then complete the movement per screen refresh where I redraw every screen element. Then when I keyUp 'w' set moveUp to false . I'm looking mostly for if this style of variable-value-parameter-passing is possible.

*EDIT: I'm looking for the keyUp/keyDown to change the variable's value which in turn ALSO directly changes the param passed to the corresponding function.

Answer 1

I don't think you need function parameters, use an object property instead. The keyup/keydown code can call player.enableMove() and player.disableMove() .

Also, addPoints() and changeVelocity() need to assign this.xxx .

 class Player { /* * @param {int} x - x position * @param {int} y - y position * @param {int} size - size of object * */ constructor(x, y, size) { this.x = x; this.y = y; this.size = size; this.points = 0; this.velocity = 1; this.color = 'white'; this.canMove = true; } addPoints(amount) { this.points += amount; } changeVelocity(newVelocity) { this.velocity = newVelocity; } enableMove() { this.canMove = true; } disableMove() { this.canMove = false; } moveLeft = function() { if (this.canMove) { this.x -= this.velocity; } } moveRight = function() { if (this.canMove) { this.x += this.velocity; } } moveUp = function() { if (this.canMove) { this.y -= this.velocity; } } moveDown = function() { if (this.canMove) { this.y += this.velocity; } } }