Angular2 Typescript声明变量任何抛出ReferenceError

Question

Hi StackOverflow community,

I have JavaScript code outside which set global js variable, but in some cases this variable does not exist. I have configuration class in Angular2 which import that global variable via declare var any. In the class I have static variable with ternary operator which checks if this global variable exists (!=null) then set some statement but it throws: Uncaught ReferenceError: IMPORTED_VAR is not defined. How to solve it?

declare var IMPORTED_VAR:any;
export class ConfigurationClass {
  public static CONF_VAR = IMPORTED_VAR ? IMPORTED_VAR : "SOMETHING";
}

Answer 1

最后，我在Typescript中创建了带有此异常的静态构造函数

Answer 2

declare var IMPORTED_VAR:any;
export class ConfigurationClass {
  public static CONF_VAR = (IMPORTED_VAR.hasOwnProperty("length") && IMPORTED_VAR.length>0) ? IMPORTED_VAR : "SOMETHING";
}