GraphQL JS Tree Parser

Common errors

• Cannot find module 'graphql-js-tree' or its corresponding type declarations.

  cause The `graphql-js-tree` package is not installed in the project, or the import path is incorrect, or TypeScript cannot find its declaration files.
  fix Ensure the package is installed: `npm install graphql-js-tree` or `yarn add graphql-js-tree`. Verify the import statement for correct path and symbol names.

• TypeError: Parser.parse is not a function

  cause Attempting to call `Parser` directly as a function or importing `Parser` incorrectly (e.g., as a default import when it's a named export).
  fix Ensure `Parser` is imported as a named export: `import { Parser } from 'graphql-js-tree';` and then called as `Parser.parse(...)`.

Warnings

• breaking Upgrading from `graphql-js-tree` v1.x to v3.x involves significant breaking changes. The internal API for `Parser` and related utilities has been refactored to achieve a 'simplier structure' as described in release notes. Code written for v1.x will likely require substantial updates.
  Fix: Consult the official GitHub repository's release notes or commit history for specific migration details between major versions. Update code to align with the new API surface and data structures.
• gotcha Ensure your project's `graphql` package version precisely matches the peer dependency requirement (`^16.0.0 || ^17.0.0`). Mismatches can lead to cryptic runtime errors due to different GraphQL AST node structures or API incompatibilities from the underlying `graphql-js` library.
  Fix: Install a compatible `graphql` version (e.g., `npm install graphql@17`). Use `npm ls graphql` or `yarn why graphql` to check for and resolve version conflicts in your dependency tree.

Install

• npm install graphql-js-tree npm
• yarn add graphql-js-tree yarn
• pnpm add graphql-js-tree pnpm

Imports

• Parser, TreeToGraphQL
  wrong:

  const { Parser, TreeToGraphQL } = require('graphql-js-tree');

  correct:

  import { Parser, TreeToGraphQL } from 'graphql-js-tree';

  The library primarily uses ES Module syntax. While CJS may work via transpilation in some setups, direct `require` is not the idiomatic way for modern applications and can lead to issues with type inference or bundling.
• parseGql
  wrong:

  import parseGql from 'graphql-js-tree';

  correct:

  import { parseGql } from 'graphql-js-tree';

  This is a named export for parsing GraphQL query strings against a schema. Do not use a default import.
• parseGqlTrees
  wrong:

  const gqlString = parseGqlTrees(parsedTrees); // Missing import

  correct:

  import { parseGqlTrees } from 'graphql-js-tree';

  While shown in README usage, `parseGqlTrees` must be explicitly imported as a named export. It is used to reconstruct a GraphQL query string from a parsed tree structure.

Quickstart

This quickstart demonstrates parsing a GraphQL SDL schema into `graphql-js-tree`'s simplified internal representation and then reconstructing it back into an SDL string, showcasing the core `Parser` and `TreeToGraphQL` functionalities.

import { Parser, TreeToGraphQL } from 'graphql-js-tree';

const schemaFileContents = `
type Query{
    hello: String!
    greeting(name: String!): String!
}
type Mutation {
    setName(name: String!): String!
}
schema{
    query: Query
    mutation: Mutation
}
`;

// Parse a GraphQL SDL schema into the simplified tree structure
const parsedSchema = Parser.parse(schemaFileContents);

// In a real application, you might process or transform 'parsedSchema' here.
// For demonstration, we'll log a portion of it.
// console.log(JSON.stringify(parsedSchema, null, 2));

// Convert the simplified tree back into a GraphQL SDL string
const graphqlString = TreeToGraphQL.parse(parsedSchema);

console.log("Original Schema:\n", schemaFileContents);
console.log("----------------------------------");
console.log("Parsed and Reconstructed Schema:\n", graphqlString);

// This demonstrates both parsing into the internal tree format and
// reconstructing the SDL, validating the transformation process.