csv-writer/src/test/csv-stringifiers/object.test.ts

Convert objects/arrays into a CSV string or write them into a CSV file

import {resolveDelimiterChar} from '../helper/delimiter';
import {createObjectCsvStringifier} from '../../index';
import {strictEqual, throws} from 'assert';

describe('ObjectCsvStringifier', () => {
    const records = [
        {FIELD_A: 'VALUE_A1', FIELD_B: 'VALUE_B1'},
        {FIELD_A: 'VALUE_A2', FIELD_B: 'VALUE_B2', OTHERS: {FIELD_C: 'VALUE_C2'}}
    ];

    describe('When field delimiter is comma', generateTestCases());

    describe('When field delimiter is semicolon', generateTestCases(';'));

    describe('When field delimiter is neither comma nor semicolon', () => {
        it('throws an exception', () => {
            throws(() => {
                createObjectCsvStringifier({
                    header: ['FIELD_A', 'FIELD_B'],
                    fieldDelimiter: '/'
                });
            });
        });
    });

    describe('When record delimiter is neither LF nor CR+LF', () => {
        it('throws an exception', () => {
            throws(() => {
                createObjectCsvStringifier({
                    header: ['FIELD_A', 'FIELD_B'],
                    recordDelimiter: '\r'
                });
            });
        });
    });

    describe('When records input is an iterable other than an array', () => {
        const stringifier = createObjectCsvStringifier({
            header: ['FIELD_A', 'FIELD_B']
        });
        function * recordGenerator() {
            yield records[0];
            yield records[1];
        }

        it('converts the records into CSV', () => {
            strictEqual(
                stringifier.stringifyRecords(recordGenerator()),
                'VALUE_A1,VALUE_B1\nVALUE_A2,VALUE_B2\n'
            );
        });
    });

    describe('When `alwaysQuote` flag is set', () => {
        const stringifier = createObjectCsvStringifier({
            header: [
                {id: 'FIELD_A', title: 'TITLE_A'},
                {id: 'FIELD_B', title: 'TITLE_B'}
            ],
            alwaysQuote: true
        });

        it('quotes all header fields', () => {
            strictEqual(stringifier.getHeaderString(), '"TITLE_A","TITLE_B"\n');
        });

        it('quotes all data fields', () => {
            strictEqual(stringifier.stringifyRecords(records), '"VALUE_A1","VALUE_B1"\n"VALUE_A2","VALUE_B2"\n');
        });
    });

    describe('When `headerIdDelimiter` is set', () => {
        const stringifier = createObjectCsvStringifier({
            header: [
                {id: 'FIELD_A', title: 'TITLE_A'},
                {id: 'OTHERS/FIELD_C', title: 'TITLE_C'}
            ],
            headerIdDelimiter: '/'
        });

        it('uses the title as is', () => {
            strictEqual(stringifier.getHeaderString(), 'TITLE_A,TITLE_C\n');
        });

        it('picks up a value in nested objects', () => {
            strictEqual(stringifier.stringifyRecords(records), 'VALUE_A1,\nVALUE_A2,VALUE_C2\n');
        });
    });

    function generateTestCases(fieldDelimiter?: string) {
        const delim = resolveDelimiterChar(fieldDelimiter);
        return () => {
            describe('header is specified with title', () => {
                const stringifier = createObjectCsvStringifier({
                    header: [
                        {id: 'FIELD_A', title: 'TITLE_A'},
                        {id: 'FIELD_B', title: 'TITLE_B'}
                    ],
                    fieldDelimiter
                });

                it(`returns a header line with field separated by "${delim}"`, () => {
                    strictEqual(stringifier.getHeaderString(), `TITLE_A${delim}TITLE_B\n`);
                });

                it(`converts given data records into CSV lines with field separated by "${delim}"`, () => {
                    strictEqual(
                        stringifier.stringifyRecords(records),
                        `VALUE_A1${delim}VALUE_B1\nVALUE_A2${delim}VALUE_B2\n`
                    );
                });
            });

            describe('header is specified without title', () => {
                const stringifier = createObjectCsvStringifier({
                    header: ['FIELD_A', 'FIELD_B'],
                    fieldDelimiter
                });

                it('returns null for header line', () => {
                    strictEqual(stringifier.getHeaderString(), null);
                });

                it(`converts given data records into CSV lines with field separated by "${delim}"`, () => {
                    strictEqual(
                        stringifier.stringifyRecords(records),
                        `VALUE_A1${delim}VALUE_B1\nVALUE_A2${delim}VALUE_B2\n`
                    );
                });
            });

            describe('header columns are given with reverse order', () => {
                const stringifier = createObjectCsvStringifier({
                    header: [
                        {id: 'FIELD_B', title: 'TITLE_B'},
                        {id: 'FIELD_A', title: 'TITLE_A'}
                    ],
                    fieldDelimiter
                });

                it(`layouts fields with the order of headers given with field separated by "${delim}"`, () => {
                    strictEqual(
                        stringifier.stringifyRecords(records),
                        `VALUE_B1${delim}VALUE_A1\nVALUE_B2${delim}VALUE_A2\n`
                    );
                });
            });
        };
    }
});