Strict Mode error when attempting to programmatically delete a relation field element

Questions and Answers
1
System Information
  • strapi": "^3.2.3
  • Mac OS 10.9
  • MongoDB Atlas
  • Node v12.14.1
  • NPM 6.14.5
  • Yarn 1.22.4

I’m wondering if anyone has encountered the issue I’m having with attempting to programmatically delete an element from a relation field. The relation field is an array. I can easily add element objects to the relation, but when I attempt to delete an element I get a Javascript Strict Mode error:

  • TypeError – Can’t delete non-configurable array element (message returned by FireFox)
  • TypeError – Cannot delete property ‘1’ of [object Array] (message returned by Chrome)

Both of the error messages refer to the same Strict Mode Error relating to not allowing the shortening of a non-configurable array.

Clearly, there is a way to do this since I can delete a relation element from the Strapi UI panel. My code follows:

   // get index of object
      let updateValue = cartItems
        .map(function (item) {
          return item.id;
        })
        .indexOf(currentUser);
        console.log("updateValue " + updateValue);  // this returns 1 as the index position of the target element in a two-item array.
      // remove object
      cartItems.splice(updateValue, 1);

The code above finds the index of the target element, but the Array.splice() method fails, reporting the non-configurable array error.

Thoughts?

Thanks… Jim

2

Excuse my ignorance as I’m much more devops focused and still learning the finer code skills in javascript. Would it not be easier to just use a .map and a delete path.in.the.object to iterate over the array of objects and delete the key(s) similar to our guide in the docs?

3

@Dmehaffy, thanks for your feedback. I followed the Strapi controller docs and after playing around with many different iterations of the code below, I’m still stuck.

`const { parseMultipartData, sanitizeEntity } = require(“strapi-utils”);

module.exports = {

async update(ctx) {
const { id } = ctx.params;
const { user } = ctx.state;

let entity;
if (ctx.is("multipart")) {
  const { data, files } = parseMultipartData(ctx);
  entity = await strapi.services.product.update({ id }, data, {
    files,
  });
} else {
  // return id; = 5fa47483e87eddaad31766c6 from const { id } = ctx.params;
  entity = await strapi.services.product
    .update({ id }, ctx.request.body, {
      $pull: {
        userCarts: {
          _id: "5f832758ef13ed4f801c8937",
        },
      },
    })
}
return sanitizeEntity(entity, { model: strapi.models.product });

}
}`

My product is returned but the userCarts item is not deleted.

I also tested code that was suggested on Strapi’s Slack channel by replacing:
entity = await strapi.services.product.update(

with

entity = await strapi.query("product").model.updateOne(

No joy on that code change, either.

Mongoose $pull seems to have a history of issues related to not working. From what I’ve read, it essentially depends on “_id”, though some have had success using other fields as target values. “_id” is my target value for userCarts.

Does Strapi have its own implementation for $pull?

Thoughts?

Thanks… Jim