openapi-typescript-codegen/src/utils/readSpecFromDisk.ts

import { resolve } from 'path';

import { exists, readFile } from './fileSystem';

/**
 * Check if given file exists and try to read the content as string.
 * @param input
 */
export async function readSpecFromDisk(input: string): Promise<string> {
    const filePath = resolve(process.cwd(), input);
    const fileExists = await exists(filePath);
    if (fileExists) {
        try {
            const content = await readFile(filePath, 'utf8');
            return content.toString();
        } catch (e) {
            throw new Error(`Could not read OpenApi spec: "${filePath}"`);
        }
    }
    throw new Error(`Could not find OpenApi spec: "${filePath}"`);
}