Developer
53 lines
1.7 KiB
TypeScript
53 lines
1.7 KiB
TypeScript
import { Logger } from '@nestjs/common';
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const logger = new Logger('JsonUtils');
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/**
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* Safely parses JSON from a string, handling markdown code blocks and leading/trailing text.
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*/
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export function safeParseJson<T = any>(text: string): T | null {
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if (!text) return null;
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let jsonStr = text.trim();
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// 1. Try to extract JSON from markdown code blocks if they exist
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// Matches ```json ... ``` or just ``` ... ```
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const codeBlockRegex = /```(?:json)?\s*([\s\S]*?)\s*```/i;
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const match = jsonStr.match(codeBlockRegex);
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if (match && match[1]) {
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jsonStr = match[1].trim();
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} else {
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// 2. If no markdown block, try to find the start and end of JSON characters
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// This handles cases where the AI adds introductory or concluding text outside the block
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const firstOpenBrace = jsonStr.indexOf('{');
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const firstOpenBracket = jsonStr.indexOf('[');
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let startIndex = -1;
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if (firstOpenBrace !== -1 && (firstOpenBracket === -1 || firstOpenBrace < firstOpenBracket)) {
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startIndex = firstOpenBrace;
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} else if (firstOpenBracket !== -1) {
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startIndex = firstOpenBracket;
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}
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if (startIndex !== -1) {
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const lastCloseBrace = jsonStr.lastIndexOf('}');
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const lastCloseBracket = jsonStr.lastIndexOf(']');
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const endIndex = Math.max(lastCloseBrace, lastCloseBracket);
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if (endIndex !== -1 && endIndex > startIndex) {
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jsonStr = jsonStr.substring(startIndex, endIndex + 1);
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}
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}
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}
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try {
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return JSON.parse(jsonStr) as T;
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} catch (error) {
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logger.error('[safeParseJson] Failed to parse JSON:', error);
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logger.error('[safeParseJson] Original text:', text);
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logger.error('[safeParseJson] Extracted string:', jsonStr);
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return null;
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}
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}
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