From 020c1e77489b772f854bb3288b9c8d2818a6bf9d Mon Sep 17 00:00:00 2001 From: EuAndreh Date: Fri, 18 Apr 2025 02:17:12 -0300 Subject: git mv src/content/* src/content/en/ --- src/content/tils/2021/08/11/js-bigint-reviver.adoc | 89 ---------------------- 1 file changed, 89 deletions(-) delete mode 100644 src/content/tils/2021/08/11/js-bigint-reviver.adoc (limited to 'src/content/tils/2021/08') diff --git a/src/content/tils/2021/08/11/js-bigint-reviver.adoc b/src/content/tils/2021/08/11/js-bigint-reviver.adoc deleted file mode 100644 index 98ee79b..0000000 --- a/src/content/tils/2021/08/11/js-bigint-reviver.adoc +++ /dev/null @@ -1,89 +0,0 @@ -= Encoding and decoding JavaScript BigInt values with reviver -:updatedat: 2021-08-13 - -:reviver-fn: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse#using_the_reviver_parameter -:bigint: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt -:json-rfc: https://datatracker.ietf.org/doc/html/rfc8259 - -`JSON.parse()` accepts a second parameter: a {reviver-fn}[`reviver()` function]. -It is a function that can be used to transform the `JSON` values as they're -being parsed. - -As it turns out, when combined with JavaScript's {bigint}[`BigInt`] type, you -can parse and encode JavaScript `BigInt` numbers via JSON: - -[source,javascript] ----- -const bigIntReviver = (_, value) => - typeof value === "string" && value.match(/^-?[0-9]+n$/) - ? BigInt(value.slice(0, value.length - 1)) - : value; ----- - -I chose to interpret strings that contains only numbers and an ending `n` -suffix as `BigInt` values, similar to how JavaScript interprets `123` (a number) -differently from `123n` (a `bigint`); - -We do those checks before constructing the `BigInt` to avoid throwing needless -exceptions and catching them on the parsing function, as this could easily -become a bottleneck when parsing large JSON values. - -In order to do the full roundtrip, we now only need the `toJSON()` counterpart: - -[source,javascript] ----- -BigInt.prototype.toJSON = function() { - return this.toString() + "n"; -}; ----- - -With both `bigIntReviver` and `toJSON` defined, we can now successfully parse -and encode JavaScript objects with `BigInt` values transparently: - -[source,javascript] ----- -const s = `[ - null, - true, - false, - -1, - 3.14, - "a string", - { "a-number": "-123" }, - { "a-bigint": "-123n" } -]`; - -const parsed = JSON.parse(s, bigIntReviver); -const s2 = JSON.stringify(parsed); - -console.log(parsed); -console.log(s2); - -console.log(typeof parsed[6]["a-number"]) -console.log(typeof parsed[7]["a-bigint"]) ----- - -The output of the above is: - -[source,javascript] ----- -[ - null, - true, - false, - -1, - 3.14, - 'a string', - { 'a-number': '-123' }, - { 'a-bigint': -123n } -] -[null,true,false,-1,3.14,"a string",{"a-number":"-123"},{"a-bigint":"-123n"}] -string -bigint ----- - -If you're on a web browser, you can probably try copying and pasting the above -code on the console right now, as is. - -Even though {json-rfc}[`JSON`] doesn't include `BigInt` number, encoding and -decoding them as strings is quite trivial on JavaScript. -- cgit v1.2.3