The proposal is an extension of ECMAScript to support exact decimal (base-10) numbers. Decimals are exact representations of numbers that we are familiar with in daily life. In this setting, 1.3 would be handled as the mathematical value 1.3 rather than a base-2 approximation thereof. These numbers, and the need for operating on them faithfully, are widespread when handling money but also show up in handling all sorts of human-readable/writeable numeric values.
Our current thinking about decimals is that there would be a new object in the ECMAScript standard library (the name is TBD, but is likely to be Decimal or Decimal128). No new syntax or primitive data types would be added to ECMAScript. The underlying data model would be IEEE 754 Decimal128 floating-point decimals, where values use 128 bits. (This data model allows for up to 34 significant digits, with an exponent [power of ten] of +/- 6144.) The envisioned API would contain only basic arithmetic (addition, subtraction, multiplication, division), rounding, remainder, and comparison (less-than/equals/greater-than).
As of writing, the specification is at stage 1 in the Ecma TC39 process.
WebKittens
@msaboff @annevk
Title of the spec
Ecma TC39 Decimal Numbers
URL to the spec
https://github.com/tc39/proposal-decimal
URL to the spec's repository
https://github.com/tc39/proposal-decimal
Issue Tracker URL
https://github.com/tc39/proposal-decimal/issues
Explainer URL
No response
TAG Design Review URL
No response
Mozilla standards-positions issue URL
No response
WebKit Bugzilla URL
No response
Radar URL
No response
Description
The proposal is an extension of ECMAScript to support exact decimal (base-10) numbers. Decimals are exact representations of numbers that we are familiar with in daily life. In this setting,
1.3would be handled as the mathematical value 1.3 rather than a base-2 approximation thereof. These numbers, and the need for operating on them faithfully, are widespread when handling money but also show up in handling all sorts of human-readable/writeable numeric values.Our current thinking about decimals is that there would be a new object in the ECMAScript standard library (the name is TBD, but is likely to be
DecimalorDecimal128). No new syntax or primitive data types would be added to ECMAScript. The underlying data model would be IEEE 754 Decimal128 floating-point decimals, where values use 128 bits. (This data model allows for up to 34 significant digits, with an exponent [power of ten] of +/- 6144.) The envisioned API would contain only basic arithmetic (addition, subtraction, multiplication, division), rounding, remainder, and comparison (less-than/equals/greater-than).As of writing, the specification is at stage 1 in the Ecma TC39 process.