Did you know that 0.1 + 0.2 == 0.3 equals false in JavaScript (see this useful article)?
Did you also know that packages like Big.js exist to deal with exact number issues like this?
Do you feel like an idiot for not noticing this issue sooner and now realize that your whole codebase is fucked (totally didn't happen to me btw)?
Then maybe this simple CLI tool (and library) may come to the rescue to convert your existing code to Bigs!
This utility uses the TypeScript compiler API under the hood, so it should be fast enough for tooling.
Install the CLI application globally:
$ npm install --global native-to-big
Install the package locally, for programmatic purposes:
$ npm install --save-dev native-to-big
import { convert } from 'native-to-big';
// convert raw code & log the result to console
convert({
sourceCode: 'const nr = 1 + 2 - 3;',
prependNew: true, // write 'new Big()' instead of 'Big()'
appendToNumber: true, // append '.toNumber()' at the end of each Big
variables: ['total'], // transforms 'let total = 0' to 'let total = Big(0)' whenever a variabe named 'total' is found
onConverted: (file) => {
console.log(file.getFullText());
// output: const nr = new Big(1).plus(2).minus(3).toNumber();
},
});
// convert multiple files & write them to disk
convert({
source: ['./src/**/*{.js,.ts}', './bin/main.ts'],
onConverted: (file) => file.saveSync()
});
// convert multiple files from a TypeScript project & asynchronously write them to disk
convert({
sourceTsConfig: '/path/to/project/tsconfig.json',
onConverted: async (file) => file.save()
})
.then(() => console.log('All files written successfully!'))
.catch(console.error);Usage:
$ n2b --help
Examples:
$ n2b -sc 0.1 + 0.2
$ n2b -s ./src/**/*.ts --dryRun
$ n2b --prependNew --appendToNumber --variables total,sum --sourceTsConfig ./tsconfig.json
These features are currently missing. Feel free to contribute!
- Doesn't support conversion of
Math.pow.Math.sqrtandMath.absare supported though. A warning will be logged to console whenever it's found and it will be ignored.
Other useful packages that are worth a mention: