feat(es/minifier): Compress Assign to number (#9943)

**Related issue:** - Closes #9935
swc-project · Jan 26, 2025 · d5f40a0 · d5f40a0
1 parent f7faa7c
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diff --git a/.changeset/happy-cameras-run.md b/.changeset/happy-cameras-run.md
@@ -0,0 +1,6 @@
+---
+swc_core: minor
+swc_ecma_minifier: minor
+---
+
+feat(es/minifier): Compress Assign to number
diff --git a/crates/swc_ecma_minifier/src/compress/pure/numbers.rs b/crates/swc_ecma_minifier/src/compress/pure/numbers.rs
@@ -1,4 +1,4 @@
-use swc_common::util::take::Take;
+use swc_common::{util::take::Take, EqIgnoreSpan, DUMMY_SP};
 use swc_ecma_ast::*;
 use swc_ecma_utils::num_from_str;
 
@@ -92,22 +92,50 @@ impl Pure<'_> {
     }
 
     pub(super) fn optimize_to_number(&mut self, e: &mut Expr) {
-        if let Expr::Bin(bin) = e {
-            if bin.op == op!("*")
-                && matches!(&*bin.left, Expr::Lit(Lit::Num(Number { value: 1.0, .. })))
-            {
-                report_change!("numbers: Turn '1 *' into '+'");
-                self.changed = true;
+        match e {
+            Expr::Bin(bin) => {
+                if bin.op == op!("*")
+                    && matches!(&*bin.left, Expr::Lit(Lit::Num(Number { value: 1.0, .. })))
+                {
+                    report_change!("numbers: Turn '1 *' into '+'");
+                    self.changed = true;
+
+                    let value = bin.right.take();
+                    let span = bin.span;
 
-                let value = bin.right.take();
-                let span = bin.span;
+                    *e = Expr::Unary(UnaryExpr {
+                        span,
+                        op: op!(unary, "+"),
+                        arg: value,
+                    })
+                }
+            }
+            Expr::Assign(a @ AssignExpr { op: op!("="), .. }) => {
+                if let (
+                    AssignTarget::Simple(SimpleAssignTarget::Ident(l_id)),
+                    Expr::Unary(UnaryExpr {
+                        op: op!(unary, "+"),
+                        arg,
+                        ..
+                    }),
+                ) = (&a.left, &*a.right)
+                {
+                    if let Expr::Ident(r_id) = &**arg {
+                        if l_id.id.eq_ignore_span(r_id) {
+                            report_change!("numbers: Turn a = +a into a *= 1");
+                            self.changed = true;
 
-                *e = Expr::Unary(UnaryExpr {
-                    span,
-                    op: op!(unary, "+"),
-                    arg: value,
-                })
+                            a.op = op!("*=");
+                            a.right = Box::new(Expr::Lit(Lit::Num(Number {
+                                span: DUMMY_SP,
+                                value: 1.0,
+                                raw: None,
+                            })))
+                        }
+                    }
+                }
             }
+            _ => (),
         }
     }
 }
diff --git a/crates/swc_ecma_minifier/tests/benches-full/d3.js b/crates/swc_ecma_minifier/tests/benches-full/d3.js
diff --git a/crates/swc_ecma_minifier/tests/benches-full/echarts.js b/crates/swc_ecma_minifier/tests/benches-full/echarts.js
@@ -4039,7 +4039,7 @@
     /**
      * Get precision
      */ function getPrecision(val) {
-        if (isNaN(val = +val)) return 0;
+        if (isNaN(val *= 1)) return 0;
          // It is much faster than methods converting number to string as follows
         for(//      let tmp = val.toString();
         //      return tmp.length - 1 - tmp.indexOf('.');

diff --git a/crates/swc_ecma_minifier/tests/benches-full/jquery.js b/crates/swc_ecma_minifier/tests/benches-full/jquery.js
@@ -456,7 +456,7 @@
  * @param {Function} fn
  */ function createPositionalPseudo(fn) {
             return markFunction(function(argument) {
-                return argument = +argument, markFunction(function(seed, matches) {
+                return argument *= 1, markFunction(function(seed, matches) {
                     // Match elements found at the specified indexes
                     for(var j, matchIndexes = fn([], seed.length, argument), i = matchIndexes.length; i--;)seed[j = matchIndexes[i]] && (seed[j] = !(matches[j] = seed[j]));
                 });

diff --git a/crates/swc_ecma_minifier/tests/benches-full/lodash.js b/crates/swc_ecma_minifier/tests/benches-full/lodash.js
@@ -9611,7 +9611,7 @@
      * _.map(['6', '08', '10'], _.parseInt);
      * // => [6, 8, 10]
      */ function(string, radix, guard) {
-            return guard || null == radix ? radix = 0 : radix && (radix = +radix), nativeParseInt(toString(string).replace(reTrimStart, ''), radix || 0);
+            return guard || null == radix ? radix = 0 : radix && (radix *= 1), nativeParseInt(toString(string).replace(reTrimStart, ''), radix || 0);
         }, lodash.random = /**
      * Produces a random number between the inclusive `lower` and `upper` bounds.
      * If only one argument is provided a number between `0` and the given number

diff --git a/crates/swc_ecma_minifier/tests/benches-full/victory.js b/crates/swc_ecma_minifier/tests/benches-full/victory.js
diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/2257/full/output.js b/crates/swc_ecma_minifier/tests/fixture/issues/2257/full/output.js
@@ -4838,7 +4838,7 @@
             module.exports = !$expm1 || // Old FF bug
             $expm1(10) > 22025.465794806719 || 22025.4657948067165168 > $expm1(10) || // Tor Browser bug
             -0.00000000000000002 != $expm1(-0.00000000000000002) ? function(x) {
-                return 0 == (x = +x) ? x : x > -0.000001 && x < 1e-6 ? x + x * x / 2 : exp(x) - 1;
+                return 0 == (x *= 1) ? x : x > -0.000001 && x < 1e-6 ? x + x * x / 2 : exp(x) - 1;
             } : $expm1;
         /***/ },
         /***/ 45404: /***/ function(module, __unused_webpack_exports, __webpack_require__) {
@@ -4858,7 +4858,7 @@
             // https://tc39.es/ecma262/#sec-math.log1p
             // eslint-disable-next-line es/no-math-log1p -- safe
             module.exports = Math.log1p || function(x) {
-                return (x = +x) > -0.00000001 && x < 1e-8 ? x - x * x / 2 : log(1 + x);
+                return (x *= 1) > -0.00000001 && x < 1e-8 ? x - x * x / 2 : log(1 + x);
             };
         /***/ },
         /***/ 62381: /***/ function(module) {
@@ -4867,7 +4867,7 @@
             // eslint-disable-next-line es/no-math-sign -- safe
             module.exports = Math.sign || function(x) {
                 // eslint-disable-next-line no-self-compare -- NaN check
-                return 0 == (x = +x) || x != x ? x : x < 0 ? -1 : 1;
+                return 0 == (x *= 1) || x != x ? x : x < 0 ? -1 : 1;
             };
         /***/ },
         /***/ 50277: /***/ function(module, __unused_webpack_exports, __webpack_require__) {
@@ -5675,7 +5675,7 @@
             // `ToInteger` abstract operation
             // https://tc39.es/ecma262/#sec-tointeger
             module.exports = function(argument) {
-                return isNaN(argument = +argument) ? 0 : (argument > 0 ? floor : ceil)(argument);
+                return isNaN(argument *= 1) ? 0 : (argument > 0 ? floor : ceil)(argument);
             };
         /***/ },
         /***/ 31998: /***/ function(module, __unused_webpack_exports, __webpack_require__) {
@@ -6734,7 +6734,7 @@
                 $acosh(1 / 0) != 1 / 0
             }, {
                 acosh: function(x) {
-                    return (x = +x) < 1 ? NaN : x > 94906265.62425156 ? log(x) + LN2 : log1p(x - 1 + sqrt(x - 1) * sqrt(x + 1));
+                    return (x *= 1) < 1 ? NaN : x > 94906265.62425156 ? log(x) + LN2 : log1p(x - 1 + sqrt(x - 1) * sqrt(x + 1));
                 }
             });
         /***/ },
@@ -6749,7 +6749,7 @@
                 forced: !($asinh && 1 / $asinh(0) > 0)
             }, {
                 asinh: function asinh(x) {
-                    return isFinite(x = +x) && 0 != x ? x < 0 ? -asinh(-x) : log(x + sqrt(x * x + 1)) : x;
+                    return isFinite(x *= 1) && 0 != x ? x < 0 ? -asinh(-x) : log(x + sqrt(x * x + 1)) : x;
                 }
             });
         /***/ },
@@ -6764,7 +6764,7 @@
                 forced: !($atanh && 1 / $atanh(-0) < 0)
             }, {
                 atanh: function(x) {
-                    return 0 == (x = +x) ? x : log((1 + x) / (1 - x)) / 2;
+                    return 0 == (x *= 1) ? x : log((1 + x) / (1 - x)) / 2;
                 }
             });
         /***/ },
@@ -6777,7 +6777,7 @@
                 stat: !0
             }, {
                 cbrt: function(x) {
-                    return sign(x = +x) * pow(abs(x), 1 / 3);
+                    return sign(x *= 1) * pow(abs(x), 1 / 3);
                 }
             });
         /***/ },
@@ -6926,7 +6926,7 @@
                 })
             }, {
                 sinh: function(x) {
-                    return 1 > abs(x = +x) ? (expm1(x) - expm1(-x)) / 2 : (exp(x - 1) - exp(-x - 1)) * (E / 2);
+                    return 1 > abs(x *= 1) ? (expm1(x) - expm1(-x)) / 2 : (exp(x - 1) - exp(-x - 1)) * (E / 2);
                 }
             });
         /***/ },
@@ -6939,7 +6939,7 @@
                 stat: !0
             }, {
                 tanh: function(x) {
-                    var a = expm1(x = +x), b = expm1(-x);
+                    var a = expm1(x *= 1), b = expm1(-x);
                     return a == 1 / 0 ? 1 : b == 1 / 0 ? -1 : (a - b) / (exp(x) + exp(-x));
                 }
             });

diff --git a/...ma_minifier/tests/fixture/next/33265/static/chunks/pages/index-cb36c1bf7f830e3c/output.js b/...ma_minifier/tests/fixture/next/33265/static/chunks/pages/index-cb36c1bf7f830e3c/output.js
@@ -6528,7 +6528,7 @@
                 var obj;
                 // Empty buffer means no match
                 if (0 === buffer.length) return -1;
-                if ("string" == typeof byteOffset ? (encoding = byteOffset, byteOffset = 0) : byteOffset > 0x7fffffff ? byteOffset = 0x7fffffff : byteOffset < -2147483648 && (byteOffset = -2147483648), (obj = byteOffset = +byteOffset) != obj && // byteOffset: it it's undefined, null, NaN, "foo", etc, search whole buffer
+                if ("string" == typeof byteOffset ? (encoding = byteOffset, byteOffset = 0) : byteOffset > 0x7fffffff ? byteOffset = 0x7fffffff : byteOffset < -2147483648 && (byteOffset = -2147483648), (obj = byteOffset *= 1) != obj && // byteOffset: it it's undefined, null, NaN, "foo", etc, search whole buffer
                 (byteOffset = dir ? 0 : buffer.length - 1), byteOffset < 0 && (byteOffset = buffer.length + byteOffset), byteOffset >= buffer.length) {
                     if (dir) return -1;
                     byteOffset = buffer.length - 1;
@@ -6612,10 +6612,10 @@
                 if (offset + ext > buf.length || offset < 0) throw RangeError("Index out of range");
             }
             function writeFloat(buf, value, offset, littleEndian, noAssert) {
-                return value = +value, offset >>>= 0, noAssert || checkIEEE754(buf, value, offset, 4, 3.4028234663852886e38, -340282346638528860000000000000000000000), ieee754.write(buf, value, offset, littleEndian, 23, 4), offset + 4;
+                return value *= 1, offset >>>= 0, noAssert || checkIEEE754(buf, value, offset, 4, 3.4028234663852886e38, -340282346638528860000000000000000000000), ieee754.write(buf, value, offset, littleEndian, 23, 4), offset + 4;
             }
             function writeDouble(buf, value, offset, littleEndian, noAssert) {
-                return value = +value, offset >>>= 0, noAssert || checkIEEE754(buf, value, offset, 8, 1.7976931348623157e308, -179769313486231570000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000), ieee754.write(buf, value, offset, littleEndian, 52, 8), offset + 8;
+                return value *= 1, offset >>>= 0, noAssert || checkIEEE754(buf, value, offset, 8, 1.7976931348623157e308, -179769313486231570000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000), ieee754.write(buf, value, offset, littleEndian, 52, 8), offset + 8;
             }
             exports.Buffer = Buffer, exports.SlowBuffer = function(length) {
                 return +length != length && // eslint-disable-line eqeqeq
@@ -6872,57 +6872,57 @@
             }, Buffer.prototype.readDoubleBE = function(offset, noAssert) {
                 return offset >>>= 0, noAssert || checkOffset(offset, 8, this.length), ieee754.read(this, offset, !1, 52, 8);
             }, Buffer.prototype.writeUIntLE = function(value, offset, byteLength, noAssert) {
-                if (value = +value, offset >>>= 0, byteLength >>>= 0, !noAssert) {
+                if (value *= 1, offset >>>= 0, byteLength >>>= 0, !noAssert) {
                     var maxBytes = Math.pow(2, 8 * byteLength) - 1;
                     checkInt(this, value, offset, byteLength, maxBytes, 0);
                 }
                 var mul = 1, i = 0;
                 for(this[offset] = 0xff & value; ++i < byteLength && (mul *= 0x100);)this[offset + i] = value / mul & 0xff;
                 return offset + byteLength;
             }, Buffer.prototype.writeUIntBE = function(value, offset, byteLength, noAssert) {
-                if (value = +value, offset >>>= 0, byteLength >>>= 0, !noAssert) {
+                if (value *= 1, offset >>>= 0, byteLength >>>= 0, !noAssert) {
                     var maxBytes = Math.pow(2, 8 * byteLength) - 1;
                     checkInt(this, value, offset, byteLength, maxBytes, 0);
                 }
                 var i = byteLength - 1, mul = 1;
                 for(this[offset + i] = 0xff & value; --i >= 0 && (mul *= 0x100);)this[offset + i] = value / mul & 0xff;
                 return offset + byteLength;
             }, Buffer.prototype.writeUInt8 = function(value, offset, noAssert) {
-                return value = +value, offset >>>= 0, noAssert || checkInt(this, value, offset, 1, 0xff, 0), this[offset] = 0xff & value, offset + 1;
+                return value *= 1, offset >>>= 0, noAssert || checkInt(this, value, offset, 1, 0xff, 0), this[offset] = 0xff & value, offset + 1;
             }, Buffer.prototype.writeUInt16LE = function(value, offset, noAssert) {
-                return value = +value, offset >>>= 0, noAssert || checkInt(this, value, offset, 2, 0xffff, 0), this[offset] = 0xff & value, this[offset + 1] = value >>> 8, offset + 2;
+                return value *= 1, offset >>>= 0, noAssert || checkInt(this, value, offset, 2, 0xffff, 0), this[offset] = 0xff & value, this[offset + 1] = value >>> 8, offset + 2;
             }, Buffer.prototype.writeUInt16BE = function(value, offset, noAssert) {
-                return value = +value, offset >>>= 0, noAssert || checkInt(this, value, offset, 2, 0xffff, 0), this[offset] = value >>> 8, this[offset + 1] = 0xff & value, offset + 2;
+                return value *= 1, offset >>>= 0, noAssert || checkInt(this, value, offset, 2, 0xffff, 0), this[offset] = value >>> 8, this[offset + 1] = 0xff & value, offset + 2;
             }, Buffer.prototype.writeUInt32LE = function(value, offset, noAssert) {
-                return value = +value, offset >>>= 0, noAssert || checkInt(this, value, offset, 4, 0xffffffff, 0), this[offset + 3] = value >>> 24, this[offset + 2] = value >>> 16, this[offset + 1] = value >>> 8, this[offset] = 0xff & value, offset + 4;
+                return value *= 1, offset >>>= 0, noAssert || checkInt(this, value, offset, 4, 0xffffffff, 0), this[offset + 3] = value >>> 24, this[offset + 2] = value >>> 16, this[offset + 1] = value >>> 8, this[offset] = 0xff & value, offset + 4;
             }, Buffer.prototype.writeUInt32BE = function(value, offset, noAssert) {
-                return value = +value, offset >>>= 0, noAssert || checkInt(this, value, offset, 4, 0xffffffff, 0), this[offset] = value >>> 24, this[offset + 1] = value >>> 16, this[offset + 2] = value >>> 8, this[offset + 3] = 0xff & value, offset + 4;
+                return value *= 1, offset >>>= 0, noAssert || checkInt(this, value, offset, 4, 0xffffffff, 0), this[offset] = value >>> 24, this[offset + 1] = value >>> 16, this[offset + 2] = value >>> 8, this[offset + 3] = 0xff & value, offset + 4;
             }, Buffer.prototype.writeIntLE = function(value, offset, byteLength, noAssert) {
-                if (value = +value, offset >>>= 0, !noAssert) {
+                if (value *= 1, offset >>>= 0, !noAssert) {
                     var limit = Math.pow(2, 8 * byteLength - 1);
                     checkInt(this, value, offset, byteLength, limit - 1, -limit);
                 }
                 var i = 0, mul = 1, sub = 0;
                 for(this[offset] = 0xff & value; ++i < byteLength && (mul *= 0x100);)value < 0 && 0 === sub && 0 !== this[offset + i - 1] && (sub = 1), this[offset + i] = (value / mul >> 0) - sub & 0xff;
                 return offset + byteLength;
             }, Buffer.prototype.writeIntBE = function(value, offset, byteLength, noAssert) {
-                if (value = +value, offset >>>= 0, !noAssert) {
+                if (value *= 1, offset >>>= 0, !noAssert) {
                     var limit = Math.pow(2, 8 * byteLength - 1);
                     checkInt(this, value, offset, byteLength, limit - 1, -limit);
                 }
                 var i = byteLength - 1, mul = 1, sub = 0;
                 for(this[offset + i] = 0xff & value; --i >= 0 && (mul *= 0x100);)value < 0 && 0 === sub && 0 !== this[offset + i + 1] && (sub = 1), this[offset + i] = (value / mul >> 0) - sub & 0xff;
                 return offset + byteLength;
             }, Buffer.prototype.writeInt8 = function(value, offset, noAssert) {
-                return value = +value, offset >>>= 0, noAssert || checkInt(this, value, offset, 1, 0x7f, -128), value < 0 && (value = 0xff + value + 1), this[offset] = 0xff & value, offset + 1;
+                return value *= 1, offset >>>= 0, noAssert || checkInt(this, value, offset, 1, 0x7f, -128), value < 0 && (value = 0xff + value + 1), this[offset] = 0xff & value, offset + 1;
             }, Buffer.prototype.writeInt16LE = function(value, offset, noAssert) {
-                return value = +value, offset >>>= 0, noAssert || checkInt(this, value, offset, 2, 0x7fff, -32768), this[offset] = 0xff & value, this[offset + 1] = value >>> 8, offset + 2;
+                return value *= 1, offset >>>= 0, noAssert || checkInt(this, value, offset, 2, 0x7fff, -32768), this[offset] = 0xff & value, this[offset + 1] = value >>> 8, offset + 2;
             }, Buffer.prototype.writeInt16BE = function(value, offset, noAssert) {
-                return value = +value, offset >>>= 0, noAssert || checkInt(this, value, offset, 2, 0x7fff, -32768), this[offset] = value >>> 8, this[offset + 1] = 0xff & value, offset + 2;
+                return value *= 1, offset >>>= 0, noAssert || checkInt(this, value, offset, 2, 0x7fff, -32768), this[offset] = value >>> 8, this[offset + 1] = 0xff & value, offset + 2;
             }, Buffer.prototype.writeInt32LE = function(value, offset, noAssert) {
-                return value = +value, offset >>>= 0, noAssert || checkInt(this, value, offset, 4, 0x7fffffff, -2147483648), this[offset] = 0xff & value, this[offset + 1] = value >>> 8, this[offset + 2] = value >>> 16, this[offset + 3] = value >>> 24, offset + 4;
+                return value *= 1, offset >>>= 0, noAssert || checkInt(this, value, offset, 4, 0x7fffffff, -2147483648), this[offset] = 0xff & value, this[offset + 1] = value >>> 8, this[offset + 2] = value >>> 16, this[offset + 3] = value >>> 24, offset + 4;
             }, Buffer.prototype.writeInt32BE = function(value, offset, noAssert) {
-                return value = +value, offset >>>= 0, noAssert || checkInt(this, value, offset, 4, 0x7fffffff, -2147483648), value < 0 && (value = 0xffffffff + value + 1), this[offset] = value >>> 24, this[offset + 1] = value >>> 16, this[offset + 2] = value >>> 8, this[offset + 3] = 0xff & value, offset + 4;
+                return value *= 1, offset >>>= 0, noAssert || checkInt(this, value, offset, 4, 0x7fffffff, -2147483648), value < 0 && (value = 0xffffffff + value + 1), this[offset] = value >>> 24, this[offset + 1] = value >>> 16, this[offset + 2] = value >>> 8, this[offset + 3] = 0xff & value, offset + 4;
             }, Buffer.prototype.writeFloatLE = function(value, offset, noAssert) {
                 return writeFloat(this, value, offset, !0, noAssert);
             }, Buffer.prototype.writeFloatBE = function(value, offset, noAssert) {