apisurf/lib/utilities/parseFunctionSignature.js

Analyze API surface changes between npm package versions to catch breaking changes

import { parseParameters } from './parseParameters.js';
/**
 * Parse function signature from const/let/var declarations
 */
export function parseFunctionSignature(lines, startIndex, name) {
    const fullLine = lines[startIndex];
    // Check if this is an arrow function
    const arrowFunctionMatch = fullLine.match(/export\s+(?:const|let|var)\s+\w+\s*=\s*(?:async\s+)?(?:<[^>]+>)?\s*\(/);
    if (arrowFunctionMatch) {
        // Extract the full function signature
        let fullSignature = fullLine.trim();
        // Handle multi-line signatures
        if (!fullSignature.includes(';') && !fullSignature.includes('{')) {
            for (let i = startIndex + 1; i < lines.length; i++) {
                const nextLine = lines[i].trim();
                fullSignature += ' ' + nextLine;
                if (nextLine.includes(';') || nextLine.includes('{')) {
                    break;
                }
            }
        }
        // Extract parameters and return type
        const paramMatch = fullSignature.match(/\(([^)]*)\)/);
        const returnTypeMatch = fullSignature.match(/\)\s*:\s*([^=]+)\s*=>/);
        let parameters = [];
        if (paramMatch && paramMatch[1]) {
            // Use the robust parameter parser
            parameters = parseParameters(paramMatch[1]);
        }
        const returnType = returnTypeMatch ? returnTypeMatch[1].trim() : undefined;
        // Extract just the signature part up to the arrow or opening brace
        const signatureMatch = fullSignature.match(/(export\s+(?:const|let|var)\s+\w+\s*=\s*(?:async\s+)?(?:<[^>]+>)?\s*\([^)]*\)(?:\s*:\s*[^=]+)?)\s*=>/);
        if (signatureMatch) {
            return {
                name,
                kind: 'function',
                signature: signatureMatch[1].replace(/\s+/g, ' ').trim() + ' => ...',
                parameters,
                returnType
            };
        }
    }
    return null;
}