| # Number Formatting | |
| **Task:** "Format numbers as currency and with thousand separators." | |
| ## Without Ponytail | |
| ```bash | |
| npm install numeral | |
| # or: npm install accounting | |
| ``` | |
| ```js | |
| import numeral from "numeral"; | |
| numeral(1234567.89).format("$1,234.00"); // "$1,234,567.89" | |
| numeral(0.745).format("0.0%"); // "74.5%" | |
| numeral(1500).format("0.0a"); // "1.5k" | |
| ``` | |
| ## With Ponytail | |
| ```js | |
| // ponytail: Intl.NumberFormat does this, locale-aware | |
| new Intl.NumberFormat("en-US", { style: "currency", currency: "USD" }) | |
| .format(1234567.89); | |
| // → "$1,234,567.89" | |
| new Intl.NumberFormat("en-US", { style: "percent" }) | |
| .format(0.745); | |
| // → "74.5%" | |
| new Intl.NumberFormat("en-US", { notation: "compact" }) | |
| .format(1500); | |
| // → "1.5K" | |
| ``` | |
| **1 dependency → 0 dependencies.** `Intl.NumberFormat` is built into every JS runtime, handles every locale correctly, and gets currency symbols, decimal separators, and grouping right for any market without a lookup table. A library that hardcodes formats will always be wrong for someone. | |