pretty-num

Lightweight module to convert number to a pretty human readable string.

Includes:

• from-exponential - remove exponential notation
• thousands - add thousands separators
• toPrecision - adjust precision of decimal part
• stripZeros - strip unnecessary leading and trailing zeros

Install

npm install pretty-num

Usage

import prettyNum, {PRECISION_SETTING} from 'pretty-num';

prettyNum(12.123e-10); // => '0.0000000012123'
prettyNum(0.00123456, {precision: 3}); // => '0.001'
prettyNum(0.00123456, {precision: 3, precisionSetting: PRECISION_SETTING.REDUCE_SIGNIFICANT}); // => '0.00123'
prettyNum(12345678.12345, {thousandsSeparator: ' '}); // => '12 345 678.12345'
prettyNum(12345678.12345, {decimalSeparator: ','}); // => '12345678,12345'
prettyNum('00123456789.12300e-2', {precision: 3, thousandsSeparator: ' '}); // => '1 234 567.891'

Options

thousandsSeparator

Defines the thousand grouping separator character

prettyNum(12345678.12345, {thousandsSeparator: ' '}); 
// => '12 345 678.12345'
prettyNum(12345678.12345, {thousandsSeparator: ','}); 
// => '12,345,678.12345'

separateOneDigit

Should number less than 10000 (e.g. 9999) to be separated, true by default

prettyNum(1234, {thousandsSeparator: ' ', separateOneDigit: true});
// => '1 234'
prettyNum(1234, {thousandsSeparator: ' ', separateOneDigit: false});
// => '1234'

precision

Number of decimal digits to keep when rounding. Pass falsey value to not change precision.

decimalSeparator

Separator between the integer part and the fractional part

precisionSetting

How to work with precision:

Reduce

1, REDUCE (default) - reduce precision to specified number of decimal digits, strip unnecessary ending zeros;

prettyNum(0.01023456, {precision: 3});
// => '0.01'
prettyNum(0.00001203456, {precision: 3});
// => '0'

Reduce significant

2, REDUCE_SIGNIFICANT - reduce precision to specified number of significant decimal digits, strip unnecessary ending zeros. Useful when rounding small values and they should not be rounded to 0

prettyNum(0.01023456, {precision: 3, precisionSetting: PRECISION_SETTING.REDUCE_SIGNIFICANT});
// => '0.0102'
prettyNum(0.00001203456, {precision: 3, precisionSetting: PRECISION_SETTING.REDUCE_SIGNIFICANT});
// => '0.000012'

Fixed

3, FIXED - set precision to specified number of decimal digits, pad with ending zeros if needed.

prettyNum(0.01023456, {precision: 3, precisionSetting: PRECISION_SETTING.FIXED});
// => '0.010'
prettyNum(0.00001203456, {precision: 3, precisionSetting: PRECISION_SETTING.FIXED});
// => '0.000'

Increase

4, INCREASE - pad with ending zeros to increase precision to specified number of decimal digits.

prettyNum(0.01, {precision: 4, precisionSetting: PRECISION_SETTING.INCREASE});
// => '0.0100'
prettyNum(12, {precision: 4, precisionSetting: PRECISION_SETTING.INCREASE});
// => '12.0000'
prettyNum(12.123456, {precision: 4, precisionSetting: PRECISION_SETTING.INCREASE});
// => '12.123456'

roundingMode

Specifies a rounding behavior for numerical operations capable of discarding precision. Following rounding modes are supported:

• 1, UP - Rounding mode to round away from zero.
• 2, DOWN - Rounding mode to round towards zero.
• 3, CEIL - Rounding mode to round towards positive infinity.
• 4, FLOOR - Rounding mode to round towards negative infinity.
• 5, HALF_UP - Rounding mode to round towards "nearest neighbor" unless both neighbors are equidistant, in which case round up.
• 6, HALF_DOWN - Rounding mode to round towards "nearest neighbor" unless both neighbors are equidistant, in which case round down.
• 7, HALF_EVEN - Rounding mode to round towards the "nearest neighbor" unless both neighbors are equidistant, in which case, round towards the even neighbor.

Extensive description of the modes can be found at Rounding Modes

prettyNum(123.657, {precision: 1, roundingMode: ROUNDING_MODE.DOWN}); // => "123.6"
prettyNum(123.657, {precision: 2, roundingMode: ROUNDING_MODE.CEIL}); // => "123.66"

Comparison

• This module:

• js-big-decimal: Math operations are supported, REDUCE_SIGNIFICANT, FIXED and INCREASE precisionSetting are not supported

• big.js: Math operations are supported, some precisionSetting are not supported, CEIL, FLOOR and HALF_DOWN roundingMode are not supported.

• bignumber.js: Math operations are supported, more rounding modes are supported, some precisionSetting are not supported.

License

MIT License