> This thread would apply equally well to objects (there's no such thing as a > "json object" - json is a string, and once it's parsed into an object it's > not json anymore) as to classes.
i’m not so sure when you start having classes with getters/setters/private-fields. then people begin digging rabbit-holes/silos trying to solve low-level equality-issues that shouldn’t even exist, and overall lose focus of the big-picture UX-workflow problems most of us js-devs were originally hired to solve. > On 18 Jan 2019, at 11:32 PM, Jordan Harband <[email protected]> wrote: > > This thread would apply equally well to objects (there's no such thing as a > "json object" - json is a string, and once it's parsed into an object it's > not json anymore) as to classes. > > Please stop derailing threads with your off-topic ideology about how to write > code - that belongs in a style guide, or in your own project, but not here. > > On Fri, Jan 18, 2019 at 9:28 PM kai zhu <[email protected] > <mailto:[email protected]>> wrote: > the most reliable/idiot-proof equality is by avoiding classes altogether; > stick with plain json-objects and compare their canonical-json-representation > like this real-world example [1]: > > ``` > /*jslint devel*/ > (function () { > "use strict"; > var jsonStringifyCanonical; > > jsonStringifyCanonical = function (obj, replacer, space) { > /* > * this function will JSON.stringify <obj>, > * with object-keys sorted and circular-references removed > */ > var circularSet; > var stringify; > var tmp; > stringify = function (obj) { > /* > * this function will recursively JSON.stringify obj, > * with object-keys sorted and circular-references removed > */ > // if obj is not an object or function, > // then JSON.stringify as normal > if (!( > obj > && typeof obj === "object" > && typeof obj.toJSON !== "function" > )) { > return JSON.stringify(obj); > } > // ignore circular-reference > if (circularSet.has(obj)) { > return; > } > circularSet.add(obj); > // if obj is an array, then recurse its items > if (Array.isArray(obj)) { > tmp = "[" + obj.map(function (obj) { > // recurse > tmp = stringify(obj); > return ( > typeof tmp === "string" > ? tmp > : "null" > ); > }).join(",") + "]"; > circularSet.delete(obj); > return tmp; > } > // if obj is not an array, > // then recurse its items with object-keys sorted > tmp = "{" + Object.keys(obj).sort().map(function (key) { > // recurse > tmp = stringify(obj[key]); > if (typeof tmp === "string") { > return JSON.stringify(key) + ":" + tmp; > } > }).filter(function (obj) { > return typeof obj === "string"; > }).join(",") + "}"; > circularSet.delete(obj); > return tmp; > }; > circularSet = new Set(); > return JSON.stringify(( > (typeof obj === "object" && obj) > // recurse > ? JSON.parse(stringify(obj)) > : obj > ), replacer, space); > }; > > // true > console.assert( > // {"data":{"x":1,"y":2,"z":3},"meta":{"label":"point #13"}} > jsonStringifyCanonical({ > data: {x: 1, y: 2, z: 3}, > meta: {label: "point #32"} > }) > // === {"data":{"x":1,"y":2,"z":3},"meta":{"label":"point #13"}} > === jsonStringifyCanonical({ > meta: {label: "point #32"}, > data: {z: 3, y: 2, x: 1} > }) > ); > }()); > ``` > > > [1] testing aa “==“ b by comparing their canonical json-representation > https://github.com/kaizhu256/node-utility2/blob/2018.12.30/test.js#L2903 > <https://github.com/kaizhu256/node-utility2/blob/2018.12.30/test.js#L2903> > https://github.com/kaizhu256/node-utility2/blob/2018.12.30/lib.utility2.js#L2760 > > <https://github.com/kaizhu256/node-utility2/blob/2018.12.30/lib.utility2.js#L2760> > > >> On 18 Jan 2019, at 3:39 PM, Isiah Meadows <[email protected] >> <mailto:[email protected]>> wrote: >> >> Yeah, I agree. I'd suggest overloading `==`, but that'd risk serious web >> compat issues, especially if `null`/`undefined` aren't special-cased. I feel >> an `equals` instance method added to all builtins and an `Object.equals` >> attempting that method first before performing a shallow object comparison >> would be the best solution. >> On Fri, Jan 18, 2019 at 15:24 Jordan Harband <[email protected] >> <mailto:[email protected]>> wrote: >> It's pretty important that the meaning `===` not be able to change. >> >> On Fri, Jan 18, 2019 at 10:33 AM ViliusCreator <[email protected] >> <mailto:[email protected]>> wrote: >> What about having Symbol.equals? >> >> For example, for now this is what it does: >> >> ```js >> >> class Position { >> constructor(o) { >> this.x = o.x instanceof Number ? o.x : 0 >> >> this.y = o.y instanceof Number ? o.y : 0 >> >> this.z = o.z instanceof Number ? o.z : 0 >> } >> } >> console.log(new Position({x: 10, y: 10, z: 10}) === new Position({x: 10, y: >> 10, z: 10}) >> >> ``` >> Output is of course, false. >> With `Symbol.equals`, we could make it easier, instead of >> `instance.equals(otherInstance)`. >> >> >> >> For example: >> >> ```js >> >> class Position { >> >> [Symbol.equals](oIn) { >> return oIn.x === this.x && oIn.y === this.y && oIn.z === this.z >> } >> constructor(o) { >> this.x = o.x instanceof Number ? o.x : 0 >> >> this.y = o.y instanceof Number ? o.y : 0 >> >> this.z = o.z instanceof Number ? o.z : 0 >> } >> } >> console.log(new Position({x: 10, y: 10, z: 10}) === new Position({x: 10, y: >> 10, z: 10}) >> >> ``` >> Now output would be true. >> >> This would save most of the time, instead of writing .equals and then >> surrounding everything with (). >> >> >> >> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient> >> Virus-free. www.avast.com >> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient> >> <>_______________________________________________ >> es-discuss mailing list >> [email protected] <mailto:[email protected]> >> https://mail.mozilla.org/listinfo/es-discuss >> <https://mail.mozilla.org/listinfo/es-discuss> >> _______________________________________________ >> es-discuss mailing list >> [email protected] <mailto:[email protected]> >> https://mail.mozilla.org/listinfo/es-discuss >> <https://mail.mozilla.org/listinfo/es-discuss> >> _______________________________________________ >> es-discuss mailing list >> [email protected] <mailto:[email protected]> >> https://mail.mozilla.org/listinfo/es-discuss >> <https://mail.mozilla.org/listinfo/es-discuss> >
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