Add FORMAT function for numeric formatting with thousands separators

[Copilot]

Description

Implements FORMAT(number, decimals[, locale]) function combining MySQL-style numeric formatting capabilities. Formats numbers with comma-separated thousands and configurable decimal precision.

Changes

Function Implementation (src/55functions.js)

• Added concise stdfn.FORMAT runtime function (13 lines)
• Handles null/undefined, NaN, negative numbers, string inputs
• Uses toFixed() for rounding to avoid floating-point precision issues
• Regex-based thousands separator insertion
• Uses destructuring for cleaner code

Test Coverage (test/test105-B.js)

• 8 test cases: basic formatting, negatives, nulls, table queries, precision levels, edge cases

Usage

alasql('SELECT FORMAT(1234567.89, 2)')  // "1,234,567.89"
alasql('SELECT FORMAT(-999.99, 0)')     // "-1,000"
alasql('SELECT FORMAT(price, 2) FROM products')

// In table context
alasql('CREATE TABLE prices (id INT, price DECIMAL(10,2))')
alasql('INSERT INTO prices VALUES (1, 1234.567)')
alasql('SELECT id, FORMAT(price, 2) AS formatted FROM prices')
// [{id: 1, formatted: "1,234.57"}]

Notes

Third parameter locale is reserved for future T-SQL/Oracle/PostgreSQL format string support per original issue request. Implementation aligns with MySQL's FORMAT() reference specification.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Add FORMAT function</issue_title>
<issue_description>I think about combination of these functions

• T-SQL FORMAT()
• MySQL FORMAT()

Plus there are some other Oracle and Postres formatting functions.
</issue_description>

<agent_instructions>Name the test file test/test105-B.js

</agent_instructions>

Comments on the Issue (you are @copilot in this section)

@mathiasrw Added to requests so people can vote for it

http://feathub.com/agershun/alasql/+26

• Fixes Add FORMAT function #105

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