AWS AppSync ESLint Plugin

An ESLint plugin that lints and produces errors for AWS AppSync resolvers written in JavaScript.

About

@aws-appsync/eslint-plugin catches invalid syntax in your code when leveraging the APPSYNC_JS runtime. The plugin allows you to quickly get feedback about your code during development without having to push your changes to the cloud.

The plugin provides 2 rule sets that you can use during development.

• plugin:@aws-appsync/base configures a base set of rules
• plugin:@aws-appsync/recommended provides the base rules and additional rules that requires TypeScript to be configured in your project

plugin:@aws-appsync/base

Rule Description

• no-async: Async processes and promises are not supported.
• no-await: Async processes and promises are not supported.
• no-promise: Async processes and promises are not supported.
• no-classes: Classes are not supported
• no-for: for is not supported(except for for-in and for-of, which are supported)
• no-continue: continue is not supported
• no-generators: generators are not supported
• no-yield: yield is not supported
• no-labels: labels are not supported
• no-this: this keyword is not supported
• no-try: try/catch structure is not supported
• no-while: while loops are not supported
• no-disallowed-unary-operators: ++, --, and ~ unary operators are not allowed
• no-disallowed-binary-operators: instanceof operator is not allowed
• no-regex: regex literals are not supported
• no-disallowed-re-assignment: re-assigning context and base properties of context are not allowed

plugin:@aws-appsync/recommended

• no-recursion: recursive function calls re ot allowed
• no-disallowed-methods: some methods are not allowed. See the reference for a full set of supported built-in functions
• no-function-passing: Passing functions as function arguments to functions is not allowed
• no-function-reassign: Functions cannot be reassigned
• no-function-return: functions cannot be the return value of functions

Usage

Install the plugin in your project by running

npm install -D @aws-appsync/eslint-plugin

The base configuration can be set up by adding the following:

// eslint.config.mjs
import appsync from '@aws-appsync/eslint-plugin';

/** @type {import('eslint').Linter.Config[]} */
export default [
    appsync.configs.base,
    // ...other config
];

You can use additional rules of the plugin (e.g.: in plugin:@aws-appsync/recommended) that requires the linter to parse TypeScript. These rules can catch unsupported features like recursion and disallowed method calls. To leverage these rules, setup Typescript in your project, and install this dependency:

npm i -D @typescript-eslint/parser

Set your config file to something similar to the following:

// eslint.config.mjs
import appsync from '@aws-appsync/eslint-plugin';

/** @type {import('eslint').Linter.Config[]} */
export default [
    { languageOptions: { parserOptions: { projectService: true } } },
    appsync.configs.recommended,
    // ...other config
];