@polkadot/util/format/formatBalance.js

A collection of useful utilities for @polkadot

// Copyright 2017-2022 @polkadot/util authors & contributors
// SPDX-License-Identifier: Apache-2.0
import { bnToBn } from "../bn/toBn.js";
import { isBoolean } from "../is/boolean.js";
import { isUndefined } from "../is/undefined.js";
import { formatDecimal } from "./formatDecimal.js";
import { calcSi, findSi, SI, SI_MID } from "./si.js";
const DEFAULT_DECIMALS = 0;
const DEFAULT_UNIT = SI[SI_MID].text;
let defaultDecimals = DEFAULT_DECIMALS;
let defaultUnit = DEFAULT_UNIT;

function getUnits(si, withSi, withSiFull, withUnit) {
  const unit = isBoolean(withUnit) ? SI[SI_MID].text : withUnit;
  return withSi || withSiFull ? si.value === '-' ? withUnit ? ` ${unit}` : '' : ` ${withSiFull ? `${si.text}${withUnit ? ' ' : ''}` : si.value}${withUnit ? unit : ''}` : '';
}

function getPrePost(text, decimals, forceUnit) {
  // NOTE We start at midpoint (8) minus 1 - this means that values display as
  // 123.456 instead of 0.123k (so always 6 relevant). Additionally we use ceil
  // so there are at most 3 decimal before the decimal separator
  const si = calcSi(text, decimals, forceUnit);
  const mid = text.length - (decimals + si.power);
  const prefix = text.substring(0, mid);
  const padding = mid < 0 ? 0 - mid : 0;
  const postfix = `${`${new Array(padding + 1).join('0')}${text}`.substring(mid < 0 ? 0 : mid)}0000`.substring(0, 4);
  return [si, prefix || '0', postfix];
} // Formats a string/number with <prefix>.<postfix><type> notation


function _formatBalance(input, options = true, optDecimals = defaultDecimals) {
  let text = bnToBn(input).toString();

  if (text.length === 0 || text === '0') {
    return '0';
  } // extract options - the boolean case is for backwards-compat


  const {
    decimals = optDecimals,
    forceUnit = undefined,
    withSi = true,
    withSiFull = false,
    withUnit = true
  } = isBoolean(options) ? {
    withSi: options
  } : options; // strip the negative sign so we can work with clean groupings, re-add this in the
  // end when we return the result (from here on we work with positive numbers)

  let sign = '';

  if (text[0].startsWith('-')) {
    sign = '-';
    text = text.substring(1);
  }

  const [si, prefix, postfix] = getPrePost(text, decimals, forceUnit);
  const units = getUnits(si, withSi, withSiFull, withUnit);
  return `${sign}${formatDecimal(prefix)}.${postfix}${units}`;
}

export const formatBalance = _formatBalance; // eslint-disable-next-line @typescript-eslint/unbound-method

formatBalance.calcSi = (text, decimals = defaultDecimals) => calcSi(text, decimals); // eslint-disable-next-line @typescript-eslint/unbound-method


formatBalance.findSi = findSi; // eslint-disable-next-line @typescript-eslint/unbound-method

formatBalance.getDefaults = () => {
  return {
    decimals: defaultDecimals,
    unit: defaultUnit
  };
}; // get allowable options to display in a dropdown
// eslint-disable-next-line @typescript-eslint/unbound-method


formatBalance.getOptions = (decimals = defaultDecimals) => {
  return SI.filter(({
    power
  }) => power < 0 ? decimals + power >= 0 : true);
}; // Sets the default decimals to use for formatting (ui-wide)
// eslint-disable-next-line @typescript-eslint/unbound-method


formatBalance.setDefaults = ({
  decimals,
  unit
}) => {
  defaultDecimals = isUndefined(decimals) ? defaultDecimals : Array.isArray(decimals) ? decimals[0] : decimals;
  defaultUnit = isUndefined(unit) ? defaultUnit : Array.isArray(unit) ? unit[0] : unit;
  SI[SI_MID].text = defaultUnit;
};