Query Variables

What is a variable in GraphQL context?

GraphQL has a first-class way to factor dynamic values out of the query, and pass them as a separate dictionary. These values are called variables. In our case, we are defining the object to be inserted as a mutation.

So let's define the graphql mutation to be used.

Open src/app/Todo/TodoInput.ts and add the following code:

src/app/Todo/TodoInput.ts

Copy
import { Component, OnInit, Input } from '@angular/core';
+ import { gql } from 'apollo-angular';

+ const ADD_TODO = gql `
+  mutation ($todo: String!, $isPublic: Boolean!) {
+    insert_todos(objects: {title: $todo, is_public: $isPublic}) {
+      affected_rows
+      returning {
+        id
+        title
+        created_at
+        is_completed
+      }
+    }
+  }
+ `;

@Component({
  selector: 'TodoInput',
  templateUrl: './TodoInput.template.html',
})

export class TodoInput {
  ...
}

What does this mutation do?

The mutation inserts into todos table with the $objects variable being passed as one todo type.

Awesome! We have defined our first graphql mutation.