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]> 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/lib.utility2.js#L2760 > > > On 18 Jan 2019, at 3:39 PM, Isiah Meadows <[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]> 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]> 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] >>> https://mail.mozilla.org/listinfo/es-discuss >>> >> _______________________________________________ >> es-discuss mailing list >> [email protected] >> https://mail.mozilla.org/listinfo/es-discuss >> > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss > > >
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