feat(es/minifier): Remove needless blocks (#10234)

**Description:** I postponed this while working on `dead_branch_remover` removal PR.

Author: kdy1

crates/swc/tests/fixture/issues-4xxx/4841/output/index.js

@@ -1,8 +1,6 @@
 global._processChunk = function r(r, c, i) {
  if (r) {
- if (!c) {
- return true;
- }
+ if (!c) return true;
  var i = this.write();
  return (i.callback = callback), void 0;
  }

crates/swc/tests/libs-size.snapshot.md

@@ -1,14 +1,14 @@
 | File | Original Size | Compressed Size | Gzipped Size |
 | --- | --- | --- | --- |
-| antd.js | 6.38 MiB | 2.05 MiB | 444.54 KiB |
+| antd.js | 6.38 MiB | 2.05 MiB | 444.51 KiB |
 | d3.js | 542.74 KiB | 259.02 KiB | 85.06 KiB |
-| echarts.js | 3.41 MiB | 971.34 KiB | 313.43 KiB |
-| jquery.js | 280.89 KiB | 87.09 KiB | 30.15 KiB |
+| echarts.js | 3.41 MiB | 971.32 KiB | 313.35 KiB |
+| jquery.js | 280.89 KiB | 87.12 KiB | 30.16 KiB |
 | lodash.js | 531.35 KiB | 68.18 KiB | 24.52 KiB |
-| moment.js | 169.83 KiB | 56.90 KiB | 18.18 KiB |
-| react.js | 70.45 KiB | 22.28 KiB | 8.01 KiB |
-| terser.js | 1.08 MiB | 444.89 KiB | 120.46 KiB |
-| three.js | 1.19 MiB | 628.02 KiB | 154.56 KiB |
-| typescript.js | 10.45 MiB | 3.17 MiB | 845.72 KiB |
-| victory.js | 2.30 MiB | 689.65 KiB | 153.65 KiB |
-| vue.js | 334.13 KiB | 112.97 KiB | 41.66 KiB |
+| moment.js | 169.83 KiB | 57.03 KiB | 18.20 KiB |
+| react.js | 70.45 KiB | 22.28 KiB | 8.00 KiB |
+| terser.js | 1.08 MiB | 444.92 KiB | 120.46 KiB |
+| three.js | 1.19 MiB | 628.03 KiB | 154.56 KiB |
+| typescript.js | 10.45 MiB | 3.17 MiB | 845.79 KiB |
+| victory.js | 2.30 MiB | 689.67 KiB | 153.65 KiB |
+| vue.js | 334.13 KiB | 112.95 KiB | 41.68 KiB |

crates/swc_ecma_minifier/src/compress/pure/mod.rs

@@ -637,7 +637,7 @@ impl VisitMut for Pure<'_> {
 
  {
  let ctx = Ctx {
- preserve_block: true,
+ preserve_block: false,
  ..self.ctx
  };
  s.cons.visit_mut_with(&mut *self.with_ctx(ctx));

crates/swc_ecma_minifier/tests/benches-full/echarts.js

@@ -153,9 +153,7 @@
  for("boolean" == typeof target && (deep = target, // Skip the boolean and the target
  target = arguments[i] || {}, i++), "object" == typeof target || isFunction(target) || (target = {}), i === length && (target = this, i--); i < length; i++)// Only deal with non-null/undefined values
  if (null != (options = arguments[i])) // Extend the base object
- for(name in options)// Prevent Object.prototype pollution
- // Prevent never-ending loop
- copy = options[name], "__proto__" !== name && target !== copy && (deep && copy && (jQuery.isPlainObject(copy) || (copyIsArray = Array.isArray(copy))) ? (src = target[name], clone = copyIsArray && !Array.isArray(src) ? [] : copyIsArray || jQuery.isPlainObject(src) ? src : {}, copyIsArray = !1, // Never move original objects, clone them
+ for(name in options)copy = options[name], "__proto__" !== name && target !== copy && (deep && copy && (jQuery.isPlainObject(copy) || (copyIsArray = Array.isArray(copy))) ? (src = target[name], clone = copyIsArray && !Array.isArray(src) ? [] : copyIsArray || jQuery.isPlainObject(src) ? src : {}, copyIsArray = !1, // Never move original objects, clone them
  target[name] = jQuery.extend(deep, clone, copy)) : void 0 !== copy && (target[name] = copy));
  // Return the modified object
  return target;
@@ -334,11 +332,10 @@
  {
  if (9 === nodeType) {
  if (!(elem = context.getElementById(m))) return results;
- // Support: IE, Opera, Webkit
+ else // Support: IE, Opera, Webkit
  // TODO: identify versions
  // getElementById can match elements by name instead of ID
  if (elem.id === m) return results.push(elem), results;
- // Element context
  } else // Support: IE, Opera, Webkit
  // TODO: identify versions
  // getElementById can match elements by name instead of ID
@@ -440,16 +437,23 @@
  // https://html.spec.whatwg.org/multipage/scripting.html#selector-enabled
  // https://html.spec.whatwg.org/multipage/scripting.html#selector-disabled
  if ("form" in elem) {
- return(// Check for inherited disabledness on relevant non-disabled elements:
+ // Check for inherited disabledness on relevant non-disabled elements:
  // * listed form-associated elements in a disabled fieldset
  // https://html.spec.whatwg.org/multipage/forms.html#category-listed
  // https://html.spec.whatwg.org/multipage/forms.html#concept-fe-disabled
  // * option elements in a disabled optgroup
  // https://html.spec.whatwg.org/multipage/forms.html#concept-option-disabled
  // All such elements have a "form" property.
- elem.parentNode && !1 === elem.disabled ? // Option elements defer to a parent optgroup if present
- "label" in elem ? "label" in elem.parentNode ? elem.parentNode.disabled === disabled : elem.disabled === disabled : elem.isDisabled === disabled || // Where there is no isDisabled, check manually
- /* jshint -W018 */ !disabled !== elem.isDisabled && inDisabledFieldset(elem) === disabled : elem.disabled === disabled);
+ if (elem.parentNode && !1 === elem.disabled) {
+ // Option elements defer to a parent optgroup if present
+ if ("label" in elem) if ("label" in elem.parentNode) return elem.parentNode.disabled === disabled;
+ else return elem.disabled === disabled;
+ // Support: IE 6 - 11
+ // Use the isDisabled shortcut property to check for disabled fieldset ancestors
+ return elem.isDisabled === disabled || // Where there is no isDisabled, check manually
+ /* jshint -W018 */ !disabled !== elem.isDisabled && inDisabledFieldset(elem) === disabled;
+ }
+ return elem.disabled === disabled;
  // Try to winnow out elements that can't be disabled before trusting the disabled property.
  // Some victims get caught in our net (label, legend, menu, track), but it shouldn't
  // even exist on them, let alone have a boolean value.
@@ -716,13 +720,12 @@
  */ getText = Sizzle.getText = function(elem) {
  var node, ret = "", i = 0, nodeType = elem.nodeType;
  if (nodeType) {
- if (1 === nodeType || 9 === nodeType || 11 === nodeType) {
- // Use textContent for elements
- // innerText usage removed for consistency of new lines (jQuery #11153)
- if ("string" == typeof elem.textContent) return elem.textContent;
- // Traverse its children
- for(elem = elem.firstChild; elem; elem = elem.nextSibling)ret += getText(elem);
- } else if (3 === nodeType || 4 === nodeType) return elem.nodeValue;
+ if (1 === nodeType || 9 === nodeType || 11 === nodeType) // Use textContent for elements
+ // innerText usage removed for consistency of new lines (jQuery #11153)
+ if ("string" == typeof elem.textContent) return elem.textContent;
+ else // Traverse its children
+ for(elem = elem.firstChild; elem; elem = elem.nextSibling)ret += getText(elem);
+ else if (3 === nodeType || 4 === nodeType) return elem.nodeValue;
  } else // If no nodeType, this is expected to be an array
  for(; node = elem[i++];)// Do not traverse comment nodes
  ret += getText(node);
@@ -1045,13 +1048,13 @@
  // We can't set arbitrary data on XML nodes, so they don't benefit from combinator caching
  if (xml) {
  for(; elem = elem[dir];)if ((1 === elem.nodeType || checkNonElements) && matcher(elem, context, xml)) return !0;
- } else for(; elem = elem[dir];)if (1 === elem.nodeType || checkNonElements) {
-  if (// Support: IE <9 only
-  // Defend against cloned attroperties (jQuery gh-1709)
-  uniqueCache = (outerCache = elem[expando] || (elem[expando] = {}))[elem.uniqueID] || (outerCache[elem.uniqueID] = {}), skip && skip === elem.nodeName.toLowerCase()) elem = elem[dir] || elem;
- else if ((oldCache = uniqueCache[key]) && oldCache[0] === dirruns && oldCache[1] === doneName) // Assign to newCache so results back-propagate to previous elements
+ } else for(; elem = elem[dir];)if (1 === elem.nodeType || checkNonElements) if (// Support: IE <9 only
+ // Defend against cloned attroperties (jQuery gh-1709)
+ uniqueCache = (outerCache = elem[expando] || (elem[expando] = {}))[elem.uniqueID] || (outerCache[elem.uniqueID] = {}), skip && skip === elem.nodeName.toLowerCase()) elem = elem[dir] || elem;
+ else {
+ if ((oldCache = uniqueCache[key]) && oldCache[0] === dirruns && oldCache[1] === doneName) // Assign to newCache so results back-propagate to previous elements
  return newCache[2] = oldCache[2];
- else // A match means we're done; a fail means we have to keep checking
+ // A match means we're done; a fail means we have to keep checking
  if (// Reuse newcache so results back-propagate to previous elements
  uniqueCache[key] = newCache, newCache[2] = matcher(elem, context, xml)) return !0;
  }
@@ -1329,17 +1332,17 @@
  null,
  selector,
  null
- ] : rquickExpr.exec(selector)) && (match[1] || !context)) {
-  // HANDLE: $(html) -> $(array)
-  if (!match[1]) return (elem = document.getElementById(match[2])) && (// Inject the element directly into the jQuery object
-  this[0] = elem, this.length = 1), this;
+ ] : rquickExpr.exec(selector)) && (match[1] || !context)) // HANDLE: $(html) -> $(array)
+ if (!match[1]) return (elem = document.getElementById(match[2])) && (// Inject the element directly into the jQuery object
+ this[0] = elem, this.length = 1), this;
+ else {
  // HANDLE: $(html, props)
  if (context = context instanceof jQuery ? context[0] : context, // Option to run scripts is true for back-compat
  // Intentionally let the error be thrown if parseHTML is not present
  jQuery.merge(this, jQuery.parseHTML(match[1], context && context.nodeType ? context.ownerDocument || context : document, !0)), rsingleTag.test(match[1]) && jQuery.isPlainObject(context)) for(match in context)// Properties of context are called as methods if possible
  isFunction(this[match]) ? this[match](context[match]) : this.attr(match, context[match]);
  return this;
- // HANDLE: $(expr, $(...))
+ // HANDLE: $(#id)
  }
  return !context || context.jquery ? (context || root).find(selector) : this.constructor(context).find(selector);
  // HANDLE: $(DOMElement)
@@ -3164,12 +3167,10 @@
  hooks.unqueued--, jQuery.queue(elem, "fx").length || hooks.empty.fire();
  });
  })), props)if (value = props[prop], rfxtypes.test(value)) {
- if (delete props[prop], toggle = toggle || "toggle" === value, value === (hidden ? "hide" : "show")) {
- // Pretend to be hidden if this is a "show" and
- // there is still data from a stopped show/hide
- if ("show" !== value || !dataShow || void 0 === dataShow[prop]) continue;
- hidden = !0;
- }
+ if (delete props[prop], toggle = toggle || "toggle" === value, value === (hidden ? "hide" : "show")) // Pretend to be hidden if this is a "show" and
+ // there is still data from a stopped show/hide
+ if ("show" !== value || !dataShow || void 0 === dataShow[prop]) continue;
+ else hidden = !0;
  orig[prop] = dataShow && dataShow[prop] || jQuery.style(elem, prop);
  }
  if (!(!// Bail out if this is a no-op like .hide().hide()
@@ -3505,7 +3506,7 @@
  var hooks, ret, valueIsFunction, elem = this[0];
  return arguments.length ? (valueIsFunction = isFunction(value), this.each(function(i) {
  var val;
- 1 === this.nodeType && (null == (val = valueIsFunction ? value.call(this, i, jQuery(this).val()) : value) ? val = "" : "number" == typeof val ? val += "" : Array.isArray(val) && (val = jQuery.map(val, function(value) {
+ 1 !== this.nodeType || (null == (val = valueIsFunction ? value.call(this, i, jQuery(this).val()) : value) ? val = "" : "number" == typeof val ? val += "" : Array.isArray(val) && (val = jQuery.map(val, function(value) {
  return null == value ? "" : value + "";
  })), (hooks = jQuery.valHooks[this.type] || jQuery.valHooks[this.nodeName.toLowerCase()]) && "set" in hooks && void 0 !== hooks.set(this, val, "value") || (this.value = val));
  })) : elem ? (hooks = jQuery.valHooks[elem.type] || jQuery.valHooks[elem.nodeName.toLowerCase()]) && "get" in hooks && void 0 !== (ret = hooks.get(elem, "value")) ? ret : "string" == typeof (ret = elem.value) ? ret.replace(rreturn, "") : null == ret ? "" : ret : void 0;
@@ -3956,7 +3957,7 @@
  function done(status, nativeStatusText, responses, headers) {
  var isSuccess, success, error, response, modified, statusText = nativeStatusText;
  // Ignore repeat invocations
- !completed && (completed = !0, timeoutTimer && window1.clearTimeout(timeoutTimer), // Dereference transport for early garbage collection
+ completed || (completed = !0, timeoutTimer && window1.clearTimeout(timeoutTimer), // Dereference transport for early garbage collection
  // (no matter how long the jqXHR object will be used)
  transport = void 0, // Cache response headers
  responseHeadersString = headers || "", // Set readyState
@@ -4327,14 +4328,18 @@
  jQuery.offset.setOffset(this, options, i);
  });
  var rect, win, elem = this[0];
- return elem ? elem.getClientRects().length ? (// Get document-relative position by adding viewport scroll to viewport-relative gBCR
+ if (elem) return(// Return zeros for disconnected and hidden (display: none) elements (gh-2310)
+ // Support: IE <=11 only
+ // Running getBoundingClientRect on a
+ // disconnected node in IE throws an error
+ elem.getClientRects().length ? (// Get document-relative position by adding viewport scroll to viewport-relative gBCR
  rect = elem.getBoundingClientRect(), win = elem.ownerDocument.defaultView, {
  top: rect.top + win.pageYOffset,
  left: rect.left + win.pageXOffset
  }) : {
  top: 0,
  left: 0
- } : void 0;
+ });
  },
  // position() relates an element's margin box to its offset parent's padding box
  // This corresponds to the behavior of CSS absolute positioning

crates/swc_ecma_minifier/tests/benches-full/jquery.js

@@ -10673,10 +10673,8 @@
  for(var iterIndex = -1, value = array[index += dir]; ++iterIndex < iterLength;){
  var data = iteratees[iterIndex], iteratee = data.iteratee, type = data.type, computed = iteratee(value);
  if (2 == type) value = computed;
- else if (!computed) {
- if (1 == type) continue outer;
- break outer;
- }
+ else if (!computed) if (1 == type) continue outer;
+ else break outer;
  }
  result[resIndex++] = value;
  }