adding jsonLine convertion

Author: Kledenai

src/converters/toJsonLines.ts

@@ -0,0 +1,33 @@
+import { Readable } from 'stream';
+import { JsonLinesObject, ToJsonLinesOptions } from '../types';
+
+export function toJsonLines(
+  jsonArray: JsonLinesObject[],
+  options?: ToJsonLinesOptions
+): string {
+  if (!Array.isArray(jsonArray)) {
+    throw new Error('Input must be an array of JSON objects.');
+  }
+
+  if (!jsonArray.every(item => item && typeof item === 'object' && !Array.isArray(item))) {
+    throw new Error('All elements in the array must be valid JSON objects.');
+  }
+
+  const { indent = 0, excludeKeys = [] } = options || {};
+
+  return jsonArray
+    .map(obj => {
+      const filteredObj = { ...obj };
+      excludeKeys.forEach(key => delete filteredObj[key]);
+      return JSON.stringify(filteredObj, null, indent);
+    })
+    .join('\n');
+};
+
+export function toJsonLinesStream(jsonArray: object[]): Readable {
+  if (!Array.isArray(jsonArray)) {
+      throw new Error('Input must be an array of JSON objects.');
+  }
+
+  return Readable.from(jsonArray.map(obj => JSON.stringify(obj) + '\n'));
+};

tests/toJsonLines.test.ts

@@ -0,0 +1,140 @@
+import { toJsonLines, toJsonLinesStream } from '../src/converters/toJsonLines';
+
+describe('toJsonLines', () => {
+  it('should convert an array of JSON objects to JSONLines format', () => {
+    const jsonArray: Record<string, unknown>[] = [
+      { name: 'Alice', age: 25 },
+      { name: 'Bob', age: 30 },
+    ];
+
+    const expected = `{"name":"Alice","age":25}
+{"name":"Bob","age":30}`;
+    const result = toJsonLines(jsonArray);
+
+    expect(result).toBe(expected);
+  });
+
+  it('should handle nested objects and arrays', () => {
+    const jsonArray: Record<string, unknown>[] = [
+      { name: 'Alice', details: { age: 25, city: 'New York' } },
+      { name: 'Bob', hobbies: ['reading', 'traveling'] },
+    ];
+
+    const expected = `{"name":"Alice","details":{"age":25,"city":"New York"}}
+{"name":"Bob","hobbies":["reading","traveling"]}`;
+    const result = toJsonLines(jsonArray);
+
+    expect(result).toBe(expected);
+  });
+
+  it('should handle different data types', () => {
+    const jsonArray: Record<string, unknown>[] = [
+      { number: 42, boolean: true, nullValue: null, emptyObject: {} },
+    ];
+
+    const expected = `{"number":42,"boolean":true,"nullValue":null,"emptyObject":{}}`;
+    const result = toJsonLines(jsonArray);
+
+    expect(result).toBe(expected);
+  });
+
+  it('should handle an empty array', () => {
+    const jsonArray: Record<string, unknown>[] = [];
+    const expected = '';
+    const result = toJsonLines(jsonArray);
+
+    expect(result).toBe(expected);
+  });
+
+  it('should handle large volumes of data', () => {
+    const jsonArray = Array.from({ length: 1000 }, (_, i) => ({ id: i }));
+
+    const result = toJsonLines(jsonArray);
+
+    expect(result.startsWith('{"id":0}')).toBe(true);
+    expect(result.endsWith('{"id":999}')).toBe(true);
+  });
+
+  it('should handle numeric keys in objects', () => {
+    const jsonArray: Record<string, unknown>[] = [
+      { '123': 'value' },
+    ];
+
+    const expected = `{"123":"value"}`;
+    const result = toJsonLines(jsonArray);
+
+    expect(result).toBe(expected);
+  });
+
+  it('should exclude specified keys from the objects', () => {
+    const jsonArray: Record<string, unknown>[] = [
+      { name: 'Alice', age: 25, city: 'New York' },
+      { name: 'Bob', age: 30, city: 'Los Angeles' },
+    ];
+
+    const options = { excludeKeys: ['city'] };
+    const expected = `{"name":"Alice","age":25}
+{"name":"Bob","age":30}`;
+    const result = toJsonLines(jsonArray, options);
+
+    expect(result).toBe(expected);
+  });
+});
+
+describe('toJsonLinesStream', () => {
+  it('should create a readable stream of JSONLines', async () => {
+    const jsonArray: Record<string, unknown>[] = [
+      { name: 'Alice', age: 25 },
+      { name: 'Bob', age: 30 },
+    ];
+
+    const stream = toJsonLinesStream(jsonArray);
+    const chunks: string[] = [];
+
+    for await (const chunk of stream) {
+      chunks.push(chunk.toString());
+    }
+
+    const expected = `{"name":"Alice","age":25}
+{"name":"Bob","age":30}
+`;
+    expect(chunks.join('')).toBe(expected);
+  });
+
+  it('should handle nested objects and arrays in stream', async () => {
+    const jsonArray: Record<string, unknown>[] = [
+      { name: 'Alice', details: { age: 25, city: 'New York' } },
+      { name: 'Bob', hobbies: ['reading', 'traveling'] },
+    ];
+
+    const stream = toJsonLinesStream(jsonArray);
+    const chunks: string[] = [];
+
+    for await (const chunk of stream) {
+      chunks.push(chunk.toString());
+    }
+
+    const expected = `{"name":"Alice","details":{"age":25,"city":"New York"}}
+{"name":"Bob","hobbies":["reading","traveling"]}
+`;
+    expect(chunks.join('')).toBe(expected);
+  });
+
+  it('should handle an empty array and produce an empty stream', async () => {
+    const jsonArray: Record<string, unknown>[] = [];
+    const stream = toJsonLinesStream(jsonArray);
+    const chunks: string[] = [];
+
+    for await (const chunk of stream) {
+      chunks.push(chunk.toString());
+    }
+
+    expect(chunks.join('')).toBe('');
+  });
+
+  it('should throw an error if the input is not an array', () => {
+    expect(() => toJsonLinesStream(null as unknown as Record<string, unknown>[])).toThrow(
+      'Input must be an array of JSON objects.'
+    );
+  });
+});