无法读取属性＆＃39;长度＆＃39;骨干中未定义的

Question

我在检查长度时遇到未定义的错误。请看图片

this. updateConfiguration = _.debounce(this.updateConfiguration, 300); 
 this.set({ url: (HyprLiveContext.locals.siteContext.siteSubdirectory 11 ") + (slug ? "/" + slug : "") + "/p/" + this.get("productCode)} 
 this.lastConfiguration = []; 
 this.calculateHasPriceRange(conf); conf = undefined 
 this.on('sync', this.calculateHasPriceRange); 
 var variations = this.get('variations'); variations = undefined 
 var sum = 0; sum = 0 

 !.. 0) 
  { 
  var stockArray = []; 

  for(var 1=0; i<variations.length; i++) 
  { 

可能是什么原因？

Answer 1

尝试初始化数组，并检查truthy值：

var variations = [];

if (this.get('variations')) {
    variations = this.get('variations');
}