The results of code compiled with vite and code compiled directly with esbuild are inconsistent，Decorators related issues

[alamhubb]

Describe the bug

The execution results of vite and esbuild are consistent

Reproduction

https://stackblitz.com/edit/vitejs-vite-zmqkuj?file=vite.config.ts,index.html,package.json&terminal=dev

Steps to reproduce

You can get the compiled main.ts from the developer tools at https://stackblitz.com/edit/vitejs-vite-zmqkuj?file=vite.config.ts,index.html,package.json&terminal=dev

var __create = Object.create;
var __defProp = Object.defineProperty;
var __getOwnPropDesc = Object.getOwnPropertyDescriptor;
var __knownSymbol = (name, symbol) => (symbol = Symbol[name]) ? symbol : Symbol.for("Symbol." + name);
var __typeError = (msg) => {
    throw TypeError(msg);
};
var __defNormalProp = (obj, key, value) => key in obj ? __defProp(obj, key, {
    enumerable: true,
    configurable: true,
    writable: true,
    value
}) : obj[key] = value;
var __name = (target, value) => __defProp(target, "name", {value, configurable: true});
var __decoratorStart = (base) => [, , , __create(base?.[__knownSymbol("metadata")] ?? null)];
var __decoratorStrings = ["class", "method", "getter", "setter", "accessor", "field", "value", "get", "set"];
var __expectFn = (fn) => fn !== void 0 && typeof fn !== "function" ? __typeError("Function expected") : fn;
var __decoratorContext = (kind, name, done, metadata, fns) => ({
    kind: __decoratorStrings[kind],
    name,
    metadata,
    addInitializer: (fn) => done._ ? __typeError("Already initialized") : fns.push(__expectFn(fn || null))
});
var __decoratorMetadata = (array, target) => __defNormalProp(target, __knownSymbol("metadata"), array[3]);
var __decorateElement = (array, flags, name, decorators, target, extra) => {
    var fn, it, done, ctx, access, k = flags & 7, s = !!(flags & 8), p = !!(flags & 16);
    var j = k > 3 ? array.length + 1 : k ? s ? 1 : 2 : 0, key = __decoratorStrings[k + 5];
    var initializers = k > 3 && (array[j - 1] = []), extraInitializers = array[j] || (array[j] = []);
    var desc = k && (!p && !s && (target = target.prototype), k < 5 && (k > 3 || !p) && __getOwnPropDesc(k < 4 ? target : {
        get [name]() {
            return __privateGet(this, extra);
        }, set [name](x) {
            return __privateSet(this, extra, x);
        }
    }, name));
    k ? p && k < 4 && __name(extra, (k > 2 ? "set " : k > 1 ? "get " : "") + name) : __name(target, name);
    for (var i = decorators.length - 1; i >= 0; i--) {
        ctx = __decoratorContext(k, name, done = {}, array[3], extraInitializers);
        if (k) {
            ctx.static = s, ctx.private = p, access = ctx.access = {has: p ? (x) => __privateIn(target, x) : (x) => name in x};
            if (k ^ 3) access.get = p ? (x) => (k ^ 1 ? __privateGet : __privateMethod)(x, target, k ^ 4 ? extra : desc.get) : (x) => x[name];
            if (k > 2) access.set = p ? (x, y) => __privateSet(x, target, y, k ^ 4 ? extra : desc.set) : (x, y) => x[name] = y;
        }
        it = (0, decorators[i])(k ? k < 4 ? p ? extra : desc[key] : k > 4 ? void 0 : {
            get: desc.get,
            set: desc.set
        } : target, ctx), done._ = 1;
        if (k ^ 4 || it === void 0) __expectFn(it) && (k > 4 ? initializers.unshift(it) : k ? p ? extra = it : desc[key] = it : target = it);
        else if (typeof it !== "object" || it === null) __typeError("Object expected");
        else __expectFn(fn = it.get) && (desc.get = fn), __expectFn(fn = it.set) && (desc.set = fn), __expectFn(fn = it.init) && initializers.unshift(fn);
    }
    return k || __decoratorMetadata(array, target), desc && __defProp(target, name, desc), p ? k ^ 4 ? extra : desc : target;
};
var __accessCheck = (obj, member, msg) => member.has(obj) || __typeError("Cannot " + msg);
var __privateIn = (member, obj) => Object(obj) !== obj ? __typeError('Cannot use the "in" operator on this value') : member.has(obj);
var __privateGet = (obj, member, getter) => (__accessCheck(obj, member, "read from private field"), getter ? getter.call(obj) : member.get(obj));
var __privateSet = (obj, member, value, setter) => (__accessCheck(obj, member, "write to private field"), setter ? setter.call(obj, value) : member.set(obj, value), value);
var __privateMethod = (obj, member, method) => (__accessCheck(obj, member, "access private method"), method);
var _testA_dec, _init;

function Resource(target, {kind, name}) {
    return function (initialValue) {
        console.log(222222);
        return 666;
    };
}

_testA_dec = [Resource];

class TestSerivce {
    test() {
        console.log(11111);
        console.log(this.testA);
    }
}

_init = __decoratorStart(null);
__decorateElement(_init, 5, "testA", _testA_dec, TestSerivce);
__decoratorMetadata(_init, TestSerivce);
const newc = new TestSerivce();
newc.test();

Use esbuild (0.21.5) to execute locally

npx esbuild main.ts --target=es2020 --outfile=out.js; node out.js

The resulting file is

var __create = Object.create;
var __defProp = Object.defineProperty;
var __getOwnPropDesc = Object.getOwnPropertyDescriptor;
var __knownSymbol = (name, symbol) => (symbol = Symbol[name]) ? symbol : Symbol.for("Symbol." + name);
var __typeError = (msg) => {
    throw TypeError(msg);
};
var __defNormalProp = (obj, key, value) => key in obj ? __defProp(obj, key, {
    enumerable: true,
    configurable: true,
    writable: true,
    value
}) : obj[key] = value;
var __name = (target, value) => __defProp(target, "name", {value, configurable: true});
var __decoratorStart = (base) => [, , , __create(base?.[__knownSymbol("metadata")] ?? null)];
var __decoratorStrings = ["class", "method", "getter", "setter", "accessor", "field", "value", "get", "set"];
var __expectFn = (fn) => fn !== void 0 && typeof fn !== "function" ? __typeError("Function expected") : fn;
var __decoratorContext = (kind, name, done, metadata, fns) => ({
    kind: __decoratorStrings[kind],
    name,
    metadata,
    addInitializer: (fn) => done._ ? __typeError("Already initialized") : fns.push(__expectFn(fn || null))
});
var __decoratorMetadata = (array, target) => __defNormalProp(target, __knownSymbol("metadata"), array[3]);
var __runInitializers = (array, flags, self, value) => {
    for (var i = 0, fns = array[flags >> 1], n = fns && fns.length; i < n; i++) flags & 1 ? fns[i].call(self) : value = fns[i].call(self, value);
    return value;
};
var __decorateElement = (array, flags, name, decorators, target, extra) => {
    var fn, it, done, ctx, access, k = flags & 7, s = !!(flags & 8), p = !!(flags & 16);
    var j = k > 3 ? array.length + 1 : k ? s ? 1 : 2 : 0, key = __decoratorStrings[k + 5];
    var initializers = k > 3 && (array[j - 1] = []), extraInitializers = array[j] || (array[j] = []);
    var desc = k && (!p && !s && (target = target.prototype), k < 5 && (k > 3 || !p) && __getOwnPropDesc(k < 4 ? target : {
        get [name]() {
            return __privateGet(this, extra);
        }, set [name](x) {
            return __privateSet(this, extra, x);
        }
    }, name));
    k ? p && k < 4 && __name(extra, (k > 2 ? "set " : k > 1 ? "get " : "") + name) : __name(target, name);
    for (var i = decorators.length - 1; i >= 0; i--) {
        ctx = __decoratorContext(k, name, done = {}, array[3], extraInitializers);
        if (k) {
            ctx.static = s, ctx.private = p, access = ctx.access = {has: p ? (x) => __privateIn(target, x) : (x) => name in x};
            if (k ^ 3) access.get = p ? (x) => (k ^ 1 ? __privateGet : __privateMethod)(x, target, k ^ 4 ? extra : desc.get) : (x) => x[name];
            if (k > 2) access.set = p ? (x, y) => __privateSet(x, target, y, k ^ 4 ? extra : desc.set) : (x, y) => x[name] = y;
        }
        it = (0, decorators[i])(k ? k < 4 ? p ? extra : desc[key] : k > 4 ? void 0 : {
            get: desc.get,
            set: desc.set
        } : target, ctx), done._ = 1;
        if (k ^ 4 || it === void 0) __expectFn(it) && (k > 4 ? initializers.unshift(it) : k ? p ? extra = it : desc[key] = it : target = it);
        else if (typeof it !== "object" || it === null) __typeError("Object expected");
        else __expectFn(fn = it.get) && (desc.get = fn), __expectFn(fn = it.set) && (desc.set = fn), __expectFn(fn = it.init) && initializers.unshift(fn);
    }
    return k || __decoratorMetadata(array, target), desc && __defProp(target, name, desc), p ? k ^ 4 ? extra : desc : target;
};
var __publicField = (obj, key, value) => __defNormalProp(obj, typeof key !== "symbol" ? key + "" : key, value);
var __accessCheck = (obj, member, msg) => member.has(obj) || __typeError("Cannot " + msg);
var __privateIn = (member, obj) => Object(obj) !== obj ? __typeError('Cannot use the "in" operator on this value') : member.has(obj);
var __privateGet = (obj, member, getter) => (__accessCheck(obj, member, "read from private field"), getter ? getter.call(obj) : member.get(obj));
var __privateSet = (obj, member, value, setter) => (__accessCheck(obj, member, "write to private field"), setter ? setter.call(obj, value) : member.set(obj, value), value);
var __privateMethod = (obj, member, method) => (__accessCheck(obj, member, "access private method"), method);
var _testA_dec, _init;

function Resource(target, {kind, name}) {
    return function (initialValue) {
        console.log(222222);
        return 666;
    };
}

_testA_dec = [Resource];

class TestSerivce {
    constructor() {
        __publicField(this, "testA", __runInitializers(_init, 8, this)), __runInitializers(_init, 11, this);
    }

    test() {
        console.log(11111);
        console.log(this.testA);
    }
}

_init = __decoratorStart(null);
__decorateElement(_init, 5, "testA", _testA_dec, TestSerivce);
__decoratorMetadata(_init, TestSerivce);
const newc = new TestSerivce();
newc.test();

The result of code execution is

The correct result was 666

The result obtained in

https://stackblitz.com/edit/vitejs-vite-zmqkuj?file=vite.config.ts,index.html,package.json&terminal=dev

is

System Info

System:
    OS: Windows 10 10.0.19045
    CPU: (16) x64 AMD Ryzen 7 5800X 8-Core Processor
    Memory: 7.97 GB / 31.89 GB
  Binaries:
    Node: 20.12.2 - D:\Program Files\nodejs\node.EXE
    npm: 10.5.0 - D:\Program Files\nodejs\npm.CMD
  Browsers:
    Edge: Chromium (127.0.2651.98)
    Internet Explorer: 11.0.19041.4355

Used Package Manager

npm

Logs

No response

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Make sure this is a Vite issue and not a framework-specific issue. For example, if it's a Vue SFC related bug, it should likely be reported to vuejs/core instead.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.

[stackblitz]

Start a new pull request in StackBlitz Codeflow.

• vitejs-vite-zmqkuj (Open reproduction)

[alamhubb]

Related issues

evanw/esbuild#3911 (comment)

#18101 (comment)

This problem is also caused by the decorator，Decorators related issues

#17308

[alamhubb]

evanw/esbuild#3911 (comment)

https://esbuild.github.io/content-types/#tsconfig-json

If I use a decorator

This rule is too hidden, and it does not use the configuration in tsconfig.json, so additional configuration is required.

esbuild: {
        sourcemap: false,
        target: 'es2020',
        tsconfigRaw: {
            compilerOptions: {
                useDefineForClassFields: true,
                target: 'es2020'
            }
        }
    }

This problem makes me sad. Can this rule be made better?

For example, tsconfigRaw will replace compilerOptions with the configuration in tsconfig.json by default

[hi-ogawa]

For example, tsconfigRaw will replace compilerOptions with the configuration in tsconfig.json by default

Vite should automatically read user's tsconfig.json for esbuild's tsconfigRaw and it looks working for me here https://stackblitz.com/edit/vitejs-vite-tqphgw?file=tsconfig.json

One caveat is that, when you don't have useDefineForClassFields explicitly, Vite will use useDefineForClassFields: false #13708 but this is to align with tsc instead of esbuild as a default behavior.

[alamhubb]

For example, tsconfigRaw will replace compilerOptions with the configuration in tsconfig.json by default

Vite should automatically read user's tsconfig.json for esbuild's tsconfigRaw and it looks working for me here https://stackblitz.com/edit/vitejs-vite-tqphgw?file=tsconfig.json

One caveat is that, when you don't have useDefineForClassFields explicitly, Vite will use useDefineForClassFields: false #13708 but this is to align with tsc instead of esbuild as a default behavior.

Feel your reply

That's because esbuild in your vite.config.ts contains target:es2020. If you delete target:es2020, the execution error occurs because this code in your vite sets useDefineForClassFields to false when both target and useDefineForClassFields do not exist. It does not read the configuration of tsconfig.json.

[hi-ogawa]

If you delete target:es2020, the execution error occurs

@alamhubb Right, I was merely suggesting that you can move esbuild.tsconfigRaw into tsconfig.json, but not esbuild.target. If this part is what's confusing, then this issue would be a duplicate of #13756 as you've commented there.

---

I experimented with tsc and esbuild on my own https://github.com/hi-ogawa/reproductions/tree/main/vite-18105-decorator-useDefineForClassFields and this might be still considered as esbuild's issue.
It looks like tsc supports decorators on uninitialized class fields (namely @Resource testA in your example) even when useDefineForClassFields: false, but that doesn't seem to be the case on esbuild.

[alamhubb]

If you delete target:es2020, the execution error occurs

@alamhubb Right, I was merely suggesting that you can move esbuild.tsconfigRaw into tsconfig.json, but not esbuild.target.

I understand why deleting es2020 will cause an execution error.

Because deleting es2020 will cause esbuild's default{target:esnext}.

Esnext is based on the tc39 decorator specification and does not support automatic conversion of decorators, while es2020 does.

Therefore, even if useDefineForClassFields: true is set, there will be a runtime error. However, this has nothing to do with useDefineForClassFields, but is caused by the decorator.

[alamhubb]

I experimented with tsc and esbuild on my own https://github.com/hi-ogawa/reproductions/tree/main/vite-18105-decorator-useDefineForClassFields and this might be still considered as esbuild's issue. It looks like tsc supports decorators on uninitialized class fields (namely @Resource testA in your example) even when useDefineForClassFields: false, but that doesn't seem to be the case on esbuild.

I think tsc is wrong, and esbuild is right.

According to my understanding, when useDefineForClassFields: false, decNoInit should not be a property in DecClass,

It should only be a property of DecClass when useDefineForClassFields: true.

esbuild does this, while tsc ignores useDefineForClassFields: false

I looked up the relevant documentation of ts and did not find any explanation for this part

https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-7.html#the-usedefineforclassfields-flag-and-the-declare-property-modifier

[alamhubb]

For example, tsconfigRaw will replace compilerOptions with the configuration in tsconfig.json by default

Vite should automatically read user's tsconfig.json for esbuild's tsconfigRaw and it looks working for me here https://stackblitz.com/edit/vitejs-vite-tqphgw?file=tsconfig.json

One caveat is that, when you don't have useDefineForClassFields explicitly, Vite will use useDefineForClassFields: false #13708 but this is to align with tsc instead of esbuild as a default behavior.

Thank you very much. I understand the problem. Vite can read the configuration in the tsconfig.json file correctly. The problem is vite:vue vitejs/vite-plugin-vue#444 , not vite. There is a problem with my previous test method. I did not correctly distinguish vite from vite:vue. Thank you for your answer.