CREATE script_tag: 'Required parameter missing or invalid'

[seandz]

I'm seeing this error as I try to create a script tag from the Koa back end of my Shopify CLI scaffolded app:

{ errors: { script_tag: 'Required parameter missing or invalid' } } =====responseBody in create st=====

Here is the method doing the call. I see that both the event and src parameters are there so am not sure what parameter could be missing. What could it be?

constructor(storeUri, accessToken) {
  this.storeUri = storeUri;
  this.accessToken = accessToken;
  this.scriptTagJsonUrl = `https://${this.storeUri}/admin/api/2019-10/script_tags.json`;
  
  console.log(storeUri, `=====storeUri=====`);
  console.log(this.storeUri, `=====this.storeUri=====`);
  console.log(this.scriptTagJsonUrl, `=====this.scriptTagJsonUrl=====`);
}

async createScriptTag() {
  try {
    const response = await fetch(this.scriptTagJsonUrl, {
      method: 'post'
      , headers : {
        "X-Shopify-Access-Token" : this.accessToken
      }
      , body : JSON.stringify({ script_tag : {
        event : 'onload'
        , src : `https://${HOST}/testLog.js?shop=${SHOP}`
                   }
      })
    })
    
    const responseBody = await response.json();
    console.log(responseBody, `=====responseBody in create st=====`);
    return responseBody;
  }
  catch (e) {
    return console.log(e, `=====error=====`);
  }

[seandz · Accepted solution]

Solved by adding the Accept and Content-Type headers:

      const response = await fetch(this.scriptTagJsonUrl, {
        method: 'post'
        , headers : {
          "X-Shopify-Access-Token" : this.accessToken
          , "Accept" : "application/json"
          , "Content-Type" : "application/json"
        }
        , body : JSON.stringify({
          "script_tag" : {
            "event" : 'onload'
            , "src" : `https://${HOST}/testLog.js?shop=${SHOP}`
          }
        })
      })