TypeError：无法读取未定义的属性“0”

Question

当我调用renderFrame ，尝试访问newLine[i]会抛出错误

Uncaught TypeError: Cannot read property '0' of undefined

为什么是这样？ 我已经包含了相关的代码。

rows : ["-","-","-","-","-","-","-","-","-","-",],

generateLine : function(){
    var result = new Array(10);
    for(var i = 0; i < result.length; i++){
        result[i] = " ";
    }
},

renderFrame : function(){
    var newLine = this.generateLine();
    for(var i = 0; i < this.rows.length; i++){
        console.log(newLine[i]);
    }
},

Answer 1

你忘了

return result;

在generateLine()的末尾

所以newLine现在未定义。 因此Cannot read property '0' of undefined