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feat: mangle Infinity #1385

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merged 5 commits into from
Jun 24, 2021
Merged

feat: mangle Infinity #1385

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b626064
feat: mangle Infinity
Jun 19, 2021
5f4b5fe
Add example code in Changelog.MD
Jun 19, 2021
046fafd
Update CHANGELOG.md
Jun 19, 2021
5cada16
Merge branch 'master' into mangle-Infinity
evanw Jun 24, 2021
7764a2a
fix correctness issues
evanw Jun 24, 2021
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14 changes: 6 additions & 8 deletions CHANGELOG.md
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Original file line number Diff line number Diff line change
Expand Up @@ -6,22 +6,20 @@

It's now possible to use `--target=es2021` to target the newly-released JavaScript version ES2021. The only difference between that and `--target=es2020` is that logical assignment operators such as `a ||= b` are not converted to regular assignment operators such as `a || (a = b)`.

* Minify Syntax `Infinity` to `1/0`
* Minify the syntax `Infinity` to `1 / 0` ([#1385](https://github.com/evanw/esbuild/pull/1385))

`--minify-syntax` will now minify the `Infinity` keyword to `1/0` which is less in bytes.
The `--minify-syntax` flag (automatically enabled by `--minify`) will now minify the expression `Infinity` to `1 / 0`, which uses fewer bytes:

```js
// Original code
const a = Infinity;

const b = 0 * Infinity;

// Output with "--mangle-syntax"
const a = 1/0;

const b = 0 * 1/0;
// Output with "--minify-syntax"
const a = 1 / 0;
```

This change was contributed by [@Gusted](https://github.com/Gusted).

## 0.12.9

* Allow `this` with `--define` ([#1361](https://github.com/evanw/esbuild/issues/1361))
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33 changes: 20 additions & 13 deletions internal/js_printer/js_printer.go
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Expand Up @@ -2129,23 +2129,30 @@ func (p *printer) printExpr(expr js_ast.Expr, level js_ast.L, flags printExprFla
value := e.Value
absValue := math.Abs(value)

infinity := "Infinity"
if p.options.MangleSyntax {
infinity = "1/0"
}

if value != value {
p.printSpaceBeforeIdentifier()
p.print("NaN")
} else if value == positiveInfinity {
p.printSpaceBeforeIdentifier()
p.print(infinity)
} else if value == negativeInfinity {
if level >= js_ast.LPrefix {
p.print("(-" + infinity + ")")
} else {
} else if value == positiveInfinity || value == negativeInfinity {
wrap := (p.options.MangleSyntax && level >= js_ast.LMultiply) ||
(value == negativeInfinity && level >= js_ast.LPrefix)
if wrap {
p.print("(")
}
if value == negativeInfinity {
p.printSpaceBeforeOperator(js_ast.UnOpNeg)
p.print("-" + infinity)
p.print("-")
} else {
p.printSpaceBeforeIdentifier()
}
if !p.options.MangleSyntax {
p.print("Infinity")
} else if p.options.RemoveWhitespace {
p.print("1/0")
} else {
p.print("1 / 0")
}
if wrap {
p.print(")")
}
} else {
if !math.Signbit(value) {
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63 changes: 55 additions & 8 deletions internal/js_printer/js_printer_test.go
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Expand Up @@ -932,13 +932,60 @@ func TestAvoidSlashScript(t *testing.T) {
expectPrintedMinify(t, "x = 1 << / script/.exec(y).length", "x=1<</ script/.exec(y).length;")
}

func TestMangledENumber(t *testing.T) {
expectPrintedMangle(t, "x = Infinity", "x = 1/0;\n")
expectPrintedMangle(t, "x = -Infinity+2", "x = -1/0 + 2;\n")
expectPrintedMangle(t, "x = (-Infinity+2) / 3", "x = (-1/0 + 2) / 3;\n")
func TestInfinity(t *testing.T) {
expectPrinted(t, "x = Infinity", "x = Infinity;\n")
expectPrinted(t, "x = -Infinity", "x = -Infinity;\n")
expectPrinted(t, "x = (Infinity).toString", "x = Infinity.toString;\n")
expectPrinted(t, "x = (-Infinity).toString", "x = (-Infinity).toString;\n")
expectPrinted(t, "x = (Infinity) ** 2", "x = Infinity ** 2;\n")
expectPrinted(t, "x = (-Infinity) ** 2", "x = (-Infinity) ** 2;\n")
expectPrinted(t, "x = ~Infinity", "x = ~Infinity;\n")
expectPrinted(t, "x = ~-Infinity", "x = ~-Infinity;\n")
expectPrinted(t, "x = Infinity * y", "x = Infinity * y;\n")
expectPrinted(t, "x = Infinity / y", "x = Infinity / y;\n")
expectPrinted(t, "x = y * Infinity", "x = y * Infinity;\n")
expectPrinted(t, "x = y / Infinity", "x = y / Infinity;\n")
expectPrinted(t, "throw Infinity", "throw Infinity;\n")

expectPrintedMinify(t, "x = Infinity", "x=Infinity;")
expectPrintedMinify(t, "x = -Infinity", "x=-Infinity;")
expectPrintedMinify(t, "x = (Infinity).toString", "x=Infinity.toString;")
expectPrintedMinify(t, "x = (-Infinity).toString", "x=(-Infinity).toString;")
expectPrintedMinify(t, "x = (Infinity) ** 2", "x=Infinity**2;")
expectPrintedMinify(t, "x = (-Infinity) ** 2", "x=(-Infinity)**2;")
expectPrintedMinify(t, "x = ~Infinity", "x=~Infinity;")
expectPrintedMinify(t, "x = ~-Infinity", "x=~-Infinity;")
expectPrintedMinify(t, "x = Infinity * y", "x=Infinity*y;")
expectPrintedMinify(t, "x = Infinity / y", "x=Infinity/y;")
expectPrintedMinify(t, "x = y * Infinity", "x=y*Infinity;")
expectPrintedMinify(t, "x = y / Infinity", "x=y/Infinity;")
expectPrintedMinify(t, "throw Infinity", "throw Infinity;")

expectPrintedMangle(t, "x = Infinity", "x = 1 / 0;\n")
expectPrintedMangle(t, "x = -Infinity", "x = -1 / 0;\n")
expectPrintedMangle(t, "x = (Infinity).toString", "x = (1 / 0).toString;\n")
expectPrintedMangle(t, "x = (-Infinity).toString", "x = (-1 / 0).toString;\n")
expectPrintedMangle(t, "x = Infinity ** 2", "x = (1 / 0) ** 2;\n")
expectPrintedMangle(t, "x = (-Infinity) ** 2", "x = (-1 / 0) ** 2;\n")
expectPrintedMangle(t, "x = ~Infinity", "x = ~(1 / 0);\n")
expectPrintedMangle(t, "x = ~-Infinity", "x = ~(-1 / 0);\n")
expectPrintedMangle(t, "x = Infinity * y", "x = 1 / 0 * y;\n")
expectPrintedMangle(t, "x = Infinity / y", "x = 1 / 0 / y;\n")
expectPrintedMangle(t, "x = y * Infinity", "x = y * (1 / 0);\n")
expectPrintedMangle(t, "x = y / Infinity", "x = y / (1 / 0);\n")
expectPrintedMangle(t, "throw Infinity", "throw 1 / 0;\n")

expectPrintedMangleMinify(t, "x = Infinity", "x=1/0;")
expectPrintedMangleMinify(t, "x = -Infinity+2", "x=-1/0+2;")
expectPrintedMangleMinify(t, "x = (-Infinity+2) / 3", "x=(-1/0+2)/3;")
expectPrintedMangleMinify(t, "1 + -Infinity", "1+-1/0;")
expectPrintedMangleMinify(t, "1 - -Infinity", "1- -1/0;")
expectPrintedMangleMinify(t, "x = -Infinity", "x=-1/0;")
expectPrintedMangleMinify(t, "x = (Infinity).toString", "x=(1/0).toString;")
expectPrintedMangleMinify(t, "x = (-Infinity).toString", "x=(-1/0).toString;")
expectPrintedMangleMinify(t, "x = Infinity ** 2", "x=(1/0)**2;")
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I've might overlook this but 1/0 ** 2 will result in Infinity as well. Can the parentheses be "turned off" for different level's? Or will that cause more problems 😅.

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The expressions (a / b) ** c and a / (b ** c) have different ASTs. Having minification turn one into the other is not generally correct, even if it's correct in that specific case. For example, changing console.log(0 ** Infinity ** 1); into console.log(0 ** 1 / 0 ** 1); changes the output from 0 to NaN.

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Got it, thanks for the explanation 🎉

expectPrintedMangleMinify(t, "x = (-Infinity) ** 2", "x=(-1/0)**2;")
expectPrintedMangleMinify(t, "x = ~Infinity", "x=~(1/0);")
expectPrintedMangleMinify(t, "x = ~-Infinity", "x=~(-1/0);")
expectPrintedMangleMinify(t, "x = Infinity * y", "x=1/0*y;")
expectPrintedMangleMinify(t, "x = Infinity / y", "x=1/0/y;")
expectPrintedMangleMinify(t, "x = y * Infinity", "x=y*(1/0);")
expectPrintedMangleMinify(t, "x = y / Infinity", "x=y/(1/0);")
expectPrintedMangleMinify(t, "throw Infinity", "throw 1/0;")
}