javascript - point.dist = function () { ^ ReferenceError : points is not defined

Question

此函数是从“JavaScript:权威指南”复制的，但由于某种原因它不起作用... **points.dist = function () { ^ ReferenceError: 点未定义**我对此很陌生，我不确定这样做是否正确

points.dist = function() {
    var p1 = this[0];
    var p2 = this[1];
    var a = p2.x-p1.x;
    var b = p2.y-p1.y;
    return Math.sqrt(a*a + b*b);
};

console.log(points.dist())

Answer 1

您至少应该使用默认值定义点对象

// Arrays and objects can hold other arrays and objects:
var points = [ // An array with 2 elements.
 {x:0, y:0}, // Each element is an object.
 {x:1, y:1}
];