Basic File Transform as Node Script

index.js

#!/usr/bin/env node
'use strict';

const fs = require('fs');

const filePath = process.argv[2];
if (!filePath) {
    console.error('Please provide the path to the file to transform.');
    process.exit(1);
}
if (!fs.existsSync(filePath)) {
    console.error('File at given path does not exist.');
    process.exit(1);
}
console.log('Transforming file at path: ' + filePath);

const fileContents = fs.readFileSync(filePath, 'utf8');

// Find schema names in file
const patternStart = 'export const schemas = {';
const idxStart = fileContents.indexOf(patternStart);
if (idxStart === -1) {
    console.error('Could not find start of schema definitions in file.');
    process.exit(1);
}
const idxEnd = fileContents.indexOf('};', idxStart);

const schemaNames = fileContents
    .substring(idxStart + patternStart.length, idxEnd)
    .replace(/\s/g, '')
    .split(',')
    .filter(schemaName => schemaName.length > 0);
    
// From schema names, generate the lines to append to the file
const lines = schemaNames.flatMap(schemaName => {
    return [
        `export { ${schemaName} };`,
        `export type ${schemaName} = z.output<typeof schemas.${schemaName}>;`,
        ''
    ]
});

const outputContents = fileContents + '\n\n // Individual exports of schemas: \n' + lines.join('\n');

fs.writeFileSync('./output.ts', outputContents, 'utf8');