测试中，我发现只要有id和index就可以擦除，point即使是空对象也行，请问point 有什么用呢

earse: function(){

const that = this;

const point = {};

const line1 = {

id: 0,

index: 1,

point: point,

};

that.mapCtx.eraseLines({

lines: [line1],

success: function (res) {

console.log(res,'擦拭成功')

},

fail: function (res) {

console.log(res,'擦拭失败')

},

complete: function (res) {

console.log(res,'擦拭完毕')

}

});

},