Fix Bugs in `iif` and `getDate` Functions in `functionsfactory.ts`

[pistillo]

https://github.com/surveyjs/survey-library/blob/ddb1b9d479c93351aa6e9ee9cbff3d5b3c59dde4/packages/survey-core/src/functionsfactory.ts#L232C1-L243C55

Hi,

I have identified a couple of bugs in the iif and getDate functions defined in the file packages/survey-core/src/functionsfactory.ts. Below are the details:

1. iif Function

• Bug: The condition if (!params && params.length !== 3) is incorrect. It should be if (!params || params.length !== 3) to correctly handle cases where params is null or undefined.
• Current Code:

  function iif(params: any[]): any {
    if (!params && params.length !== 3) return "";
    return params[0] ? params[1] : params[2];
  }

• Corrected Code:

  function iif(params: any[]): any {
    if (!params || params.length !== 3) return "";
    return params[0] ? params[1] : params[2];
  }

2. getDate Function

• Bug: The condition if (!params && params.length < 1) is incorrect. It should be if (!params || params.length < 1) to correctly handle cases where params is null or undefined.
• Current Code:

  function getDate(params: any[]): any {
    if (!params && params.length < 1) return null;
    if (!params[0]) return null;
    return createDate("function-getDate", params[0]);
  }

• Corrected Code:

  function getDate(params: any[]): any {
    if (!params || params.length < 1) return null;
    if (!params[0]) return null;
    return createDate("function-getDate", params[0]);
  }