CODEWITHSUNDEEP
node.jstypescriptmongoose
basse
basse

Reputation: 1339

Mongoose "property x does not exist on type y" error - still works

With Mongoose, I get error TS2339: Property 'highTemp' does not exist on type 'Location' when trying to use dot notation (model.attribute) although the code still works as intended. In the comments here I learned that using model['attribute'] yields no error.

What is the proper way to be able to use dot notation with Mongoose without errors?

Background:

location.model.ts

import mongoose = require('mongoose');

export const LocationSchema = new mongoose.Schema({
  name: String,
  lowTemp: Number,
  highTemp: Number,
});

export const Location = mongoose.model('Location', LocationSchema);

data.util.ts

import { Location } from '../models/location.model';

function temperatureModel(location: Location): number {
  const highTemp = location.highTemp;
  const lowTemp = location['lowTemp'];

  // Do the math...

  return something;
}

Building the above yields the TS2339 error on highTemp but not on lowTemp. My preferred method of using model attributes would be with dot notation as in location.highTemp. What should I do? Explicitly defining interfaces for every model sounds like pointless work..?

Upvotes: 1

Views: 3150

Answers (1)

Titian Cernicova-Dragomir
Titian Cernicova-Dragomir

Reputation: 249466

The model method accepts an interface (which needs to extends Document) which can be used to statically type the result:

export interface Location extends mongoose.Document {
    name: string,
    lowTemp: number,
    highTemp: number,
}

export const Location = mongoose.model<Location>('Location', LocationSchema);

// Usage
function temperatureModel(location: Location): number {
    const highTemp = location.highTemp; // Works
    const lowTemp = location.lowTemp; // Works
}

Upvotes: 3

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