Uncaught (in promise) TypeError: Cannot read properties of undefined (reading 'substring')

Question

I am using PnP JS in SPFx to get page content. I wanted to get content type id of the page and check if it belongs to certain content type.

I can't seem to make contain or includes function work so I have been trying to use substring to get first 44 character out so I can use it to compare but I am getting error:

Uncaught (in promise) TypeError: Cannot read properties of undefined (reading 'substring')

import { sp } from "@pnp/sp/presets/all";

public onInit(): Promise<void> {
    
    sp.setup({
      spfxContext: this.context
    });
 
   sp.web.lists.getById(this.context.pageContext.list.id.toString())
  .items.getById(this.context.pageContext.listItem.id)
  .select("ContentTypeId")
  .get()
  .then(d=>{
    console.log(d);
    
    let content:string=d.contentTypeId
    let sitecontentid:string= "0x01100912345D1CB255DA76424F860D91F20E6C4118000B8757F9909754BBB035517811AE70E"
    let contentid:string= content.substring(0,43)

    if  (contentid==sitecontent)
      
      {
        do something
        
        }

  })
 
    return Promise.resolve();
  }
}

Answer 1

Use below code inside .then() function:

let contentTypeIdString:string = d.ContentTypeId;
let siteContentTypeId:string = "0x01100912345D1CB255DA76424F860D91F20E6C4118000B8757F9909754BBB035517811AE70E";

let contentTypeId:string = contentTypeIdString ? contentTypeIdString.substring(0, 43): "";

if  (contentTypeId == siteContentTypeId){
    //Your code
    console.log("Content Type Id matched.");
} else {
    console.log("Content Type Id does not match.");
}