Function formatPlanck

formatPlanck(planck: bigint, decimals?: number): string
Convert a planck (smallest indivisible token unit) value to a human-readable decimal string.

Substrate chains store all token amounts as integer planck values. This function converts them to human-readable form (e.g. 10_000_000_000n → "1.0" for DOT with 10 decimals). Trailing zeros are trimmed but at least one fractional digit is always shown.
Parameters
- planck: bigint
  The raw planck value as a bigint. Must be non-negative.
- decimals: number = 10
  Number of decimal places for the token (default: 10 for DOT).
Returns string
A decimal string representation (e.g. "1.5", "0.0001").
Throws
If planck is negative or decimals is invalid.
Example
```
import { formatPlanck } from "@polkadot-apps/utils";

formatPlanck(10_000_000_000n);       // "1.0"       (10 decimals, DOT default)
formatPlanck(15_000_000_000n);       // "1.5"
formatPlanck(1_000_000_000_000n, 12); // "1.0"      (12 decimals, e.g. Polkadot relay)
formatPlanck(0n);                     // "0.0"
```
- Defined in packages/utils/src/planck.ts:45