@neodx/codegen

Helpers for implementing your own generation flow.

- Abstraction over file system
- Tools for generating files from templates
- Integrated helpers
- JSON (and JSONP) parsing
- prettier formatting
- package.json dependencies manipulation

Contents

$3

``typescript
import {
type Tree, // Interface
FsTree, // Tree over native FS
VirtualTree, // Empty in-memory tree. Useful for testing / dry-run / emulation
ReadonlyVirtualFsTree // Mixed behavior: read initial state from real fs, but keep all changes in memory
} from '@neodx/codegen';

// test.ts
const tree = new FsTree(__dirname);

await tree.readDir(); // ['test.ts']
await tree.delete('test.ts');
await tree.readDir(); // []
await tree.applyChanges();
`

Collects all files updates until you apply it to real FS.

Why we need this abstraction if we can just write everything directly in fs?

1. Single source of changes - we always know our context: path, current state, list of changes
2. Apply changes only when we know what everything is ok
3. Store updates - prevent unnecessary changes, maybe change something in only changed files

#### Example of that behavior

`typescript
import { FsTree, Tree } from '@neodx/codegen';
import { readdir } from 'node:fs/promises';
import { join } from 'node:path';

const path = join(__dirname, 'test');
const tree = new FsTree(path);

console.log(await readdir(path)); // []
await tree.write('new.txt', 'content');
console.log(await readdir(path)); // []
console.log(await tree.readDir()); // ['new.txt']
await tree.applyChanges();
console.log(await readdir(path)); // ['new.txt']
console.log(await tree.readDir()); // ['new.txt']
`

$3

`typescript
import {
Tree,
readTreeJson,
updateTreeJson,
writeTreeJson,
addTreePackageJsonDependencies,
removeTreePackageJsonDependencies,
formatAllChangedFilesInTree
} from '@neodx/codegen';

async function runExample(tree: Tree) {
await readTreeJson(tree, 'manifest.json'); // {}
await writeTreeJson(tree, 'manifest.json', { count: 0 });
await updateTreeJson(tree, 'manifest.json', prev => ({ ...prev, count: prev.count + 1 }));
await readTreeJson(tree, 'manifest.json'); // { count: 1 }
await addTreePackageJsonDependencies(tree, {
dependencies: {
foo: '^3.0.0'
},
devDependencies: {
bar: '*'
},
peerDependencies: {
bar: '^1.2.3'
}
});
await removeTreePackageJsonDependencies(tree, {
devDependencies: ['one'],
dependencies: ['two']
});
await formatAllChangedFilesInTree(tree);
}
`

$3

> TODO

Examples

$3

`typescript
import { type Tree, FsTree, updateTreeJson, formatAllChangedFilesInTree } from '@neodx/codegen';

async function addTsConfigPath(tree: Tree, name: string) {
await updateTreeJson(tree, 'tsconfig.base.json', prev => ({
...prev,
compilerOptions: {
...prev.compilerOptions,
paths: {
...prev.compilerOptions.paths,
[@my-org/${name}]: [./libs/${name}/src/index.ts],
[@my-org/${name}/]: [./libs/${name}/src/]
}
}
}));
}

const tree = new FsTree(process.cwd());

// ...some logic...
await addTsConfigPath(tree, 'foo');
// ...some logic...
await addTsConfigPath(tree, 'bar');
// ...some logic...
// Finally - format and save changes
await formatAllChangedFilesInTree(tree);
await tree.applyChanges();
``