use == and != to enable handling null/undefined

test/codegen/expect/DeltaBlue.js

 var DeltaBlue;
 (function(exports) {
   'use strict';
   // Function main: () → dynamic
   function main() {
     new DeltaBlue().report();
   }
   class DeltaBlue extends BenchmarkBase.BenchmarkBase {
     DeltaBlue() {
       super.BenchmarkBase("DeltaBlue");
@@ skipping 43 matching lines @@
       this.chooseMethod(dart.as(mark, core.int));
       if (!dart.notNull(this.isSatisfied())) {
         if (dart.equals(this.strength, REQUIRED)) {
           core.print("Could not satisfy a required constraint!");
         }
         return null;
       }
       this.markInputs(dart.as(mark, core.int));
       let out = this.output();
       let overridden = out.determinedBy;
-      if (overridden !== null)
+      if (overridden != null)
         overridden.markUnsatisfied();
       out.determinedBy = this;
       if (!dart.notNull(exports.planner.addPropagate(this, dart.as(mark, core.int))))
         core.print("Cycle encountered");
       out.mark = dart.as(mark, core.int);
       return overridden;
     }
     destroyConstraint() {
       if (this.isSatisfied())
         exports.planner.incrementalRemove(this);
       this.removeFromGraph();
     }
     isInput() {
       return false;
     }
   }
   class UnaryConstraint extends Constraint {
     UnaryConstraint(myOutput, strength) {
       this.myOutput = myOutput;
       this.satisfied = false;
       super.Constraint(strength);
       this.addConstraint();
     }
     addToGraph() {
       this.myOutput.addConstraint(this);
       this.satisfied = false;
     }
     chooseMethod(mark) {
-      this.satisfied = this.myOutput.mark !== mark && dart.notNull(Strength.stronger(this.strength, this.myOutput.walkStrength));
+      this.satisfied = this.myOutput.mark != mark && dart.notNull(Strength.stronger(this.strength, this.myOutput.walkStrength));
     }
     isSatisfied() {
       return this.satisfied;
     }
     markInputs(mark) {}
     output() {
       return this.myOutput;
     }
     recalculate() {
       this.myOutput.walkStrength = this.strength;
       this.myOutput.stay = !dart.notNull(this.isInput());
       if (this.myOutput.stay)
         this.execute();
     }
     markUnsatisfied() {
       this.satisfied = false;
     }
     inputsKnown(mark) {
       return true;
     }
     removeFromGraph() {
-      if (this.myOutput !== null)
+      if (this.myOutput != null)
         this.myOutput.removeConstraint(this);
       this.satisfied = false;
     }
   }
   class StayConstraint extends UnaryConstraint {
     StayConstraint(v, str) {
       super.UnaryConstraint(v, str);
     }
     execute() {}
   }
@@ skipping 11 matching lines @@
   let BACKWARD = 0;
   class BinaryConstraint extends Constraint {
     BinaryConstraint(v1, v2, strength) {
       this.v1 = v1;
       this.v2 = v2;
       this.direction = NONE;
       super.Constraint(strength);
       this.addConstraint();
     }
     chooseMethod(mark) {
-      if (this.v1.mark === mark) {
-        this.direction = this.v2.mark !== mark && dart.notNull(Strength.stronger(this.strength, this.v2.walkStrength)) ? FORWARD : NONE;
+      if (this.v1.mark == mark) {
+        this.direction = this.v2.mark != mark && dart.notNull(Strength.stronger(this.strength, this.v2.walkStrength)) ? FORWARD : NONE;
       }
-      if (this.v2.mark === mark) {
-        this.direction = this.v1.mark !== mark && dart.notNull(Strength.stronger(this.strength, this.v1.walkStrength)) ? BACKWARD : NONE;
+      if (this.v2.mark == mark) {
+        this.direction = this.v1.mark != mark && dart.notNull(Strength.stronger(this.strength, this.v1.walkStrength)) ? BACKWARD : NONE;
       }
       if (Strength.weaker(this.v1.walkStrength, this.v2.walkStrength)) {
         this.direction = Strength.stronger(this.strength, this.v1.walkStrength) ? BACKWARD : NONE;
       } else {
         this.direction = Strength.stronger(this.strength, this.v2.walkStrength) ? FORWARD : BACKWARD;
       }
     }
     addToGraph() {
       this.v1.addConstraint(this);
       this.v2.addConstraint(this);
       this.direction = NONE;
     }
     isSatisfied() {
-      return this.direction !== NONE;
+      return this.direction != NONE;
     }
     markInputs(mark) {
       this.input().mark = mark;
     }
     input() {
-      return this.direction === FORWARD ? this.v1 : this.v2;
+      return this.direction == FORWARD ? this.v1 : this.v2;
     }
     output() {
-      return this.direction === FORWARD ? this.v2 : this.v1;
+      return this.direction == FORWARD ? this.v2 : this.v1;
     }
     recalculate() {
       let ihn = this.input(), out = this.output();
       out.walkStrength = Strength.weakest(this.strength, ihn.walkStrength);
       out.stay = ihn.stay;
       if (out.stay)
         this.execute();
     }
     markUnsatisfied() {
       this.direction = NONE;
     }
     inputsKnown(mark) {
       let i = this.input();
-      return i.mark === mark || dart.notNull(i.stay) || dart.notNull(i.determinedBy === null);
+      return i.mark == mark || dart.notNull(i.stay) || dart.notNull(i.determinedBy == null);
     }
     removeFromGraph() {
-      if (this.v1 !== null)
+      if (this.v1 != null)
         this.v1.removeConstraint(this);
-      if (this.v2 !== null)
+      if (this.v2 != null)
         this.v2.removeConstraint(this);
       this.direction = NONE;
     }
   }
   class ScaleConstraint extends BinaryConstraint {
     ScaleConstraint(src, scale, offset, dest, strength) {
       this.scale = scale;
       this.offset = offset;
       super.BinaryConstraint(src, dest, strength);
     }
     addToGraph() {
       super.addToGraph();
       this.scale.addConstraint(this);
       this.offset.addConstraint(this);
     }
     removeFromGraph() {
       super.removeFromGraph();
-      if (this.scale !== null)
+      if (this.scale != null)
         this.scale.removeConstraint(this);
-      if (this.offset !== null)
+      if (this.offset != null)
         this.offset.removeConstraint(this);
     }
     markInputs(mark) {
       super.markInputs(mark);
       this.scale.mark = this.offset.mark = mark;
     }
     execute() {
-      if (this.direction === FORWARD) {
+      if (this.direction == FORWARD) {
         this.v2.value = dart.notNull(this.v1.value) * dart.notNull(this.scale.value) + dart.notNull(this.offset.value);
       } else {
         this.v1.value = ((dart.notNull(this.v2.value) - dart.notNull(this.offset.value)) / dart.notNull(this.scale.value)).truncate();
       }
     }
     recalculate() {
       let ihn = this.input(), out = this.output();
       out.walkStrength = Strength.weakest(this.strength, ihn.walkStrength);
       out.stay = dart.notNull(ihn.stay) && dart.notNull(this.scale.stay) && dart.notNull(this.offset.stay);
       if (out.stay)
@@ skipping 26 matching lines @@
       if (dart.equals(this.determinedBy, c))
         this.determinedBy = null;
     }
   }
   class Planner extends core.Object {
     Planner() {
       this.currentMark = 0;
     }
     incrementalAdd(c) {
       let mark = this.newMark();
-      for (let overridden = c.satisfy(mark); overridden !== null; overridden = overridden.satisfy(mark))
+      for (let overridden = c.satisfy(mark); overridden != null; overridden = overridden.satisfy(mark))
         ;
     }
     incrementalRemove(c) {
       let out = c.output();
       c.markUnsatisfied();
       c.removeFromGraph();
       let unsatisfied = this.removePropagateFrom(out);
       let strength = REQUIRED;
       do {
         for (let i = 0; dart.notNull(i) < dart.notNull(unsatisfied.length); i = dart.notNull(i) + 1) {
           let u = unsatisfied.get(i);
           if (dart.equals(u.strength, strength))
             this.incrementalAdd(u);
         }
         strength = strength.nextWeaker();
       } while (!dart.equals(strength, WEAKEST));
     }
     newMark() {
       return this.currentMark = dart.notNull(this.currentMark) + 1;
     }
     makePlan(sources) {
       let mark = this.newMark();
       let plan = new Plan();
       let todo = sources;
       while (dart.notNull(todo.length) > 0) {
         let c = todo.removeLast();
-        if (c.output().mark !== mark && dart.notNull(c.inputsKnown(mark))) {
+        if (c.output().mark != mark && dart.notNull(c.inputsKnown(mark))) {
           plan.addConstraint(c);
           c.output().mark = mark;
           this.addConstraintsConsumingTo(c.output(), todo);
         }
       }
       return plan;
     }
     extractPlanFromConstraints(constraints) {
       let sources = new core.List$(Constraint).from([]);
       for (let i = 0; dart.notNull(i) < dart.notNull(constraints.length); i = dart.notNull(i) + 1) {
         let c = constraints.get(i);
         if (dart.notNull(c.isInput()) && dart.notNull(c.isSatisfied()))
           sources.add(c);
       }
       return this.makePlan(sources);
     }
     addPropagate(c, mark) {
       let todo = new core.List$(Constraint).from([c]);
       while (dart.notNull(todo.length) > 0) {
         let d = todo.removeLast();
-        if (d.output().mark === mark) {
+        if (d.output().mark == mark) {
           this.incrementalRemove(c);
           return false;
         }
         d.recalculate();
         this.addConstraintsConsumingTo(d.output(), todo);
       }
       return true;
     }
     removePropagateFrom(out) {
       out.determinedBy = null;
@@ skipping 43 matching lines @@
         this.list.get(i).execute();
       }
     }
   }
   // Function chainTest: (int) → void
   function chainTest(n) {
     exports.planner = new Planner();
     let prev = null, first = null, last = null;
     for (let i = 0; dart.notNull(i) <= dart.notNull(n); i = dart.notNull(i) + 1) {
       let v = new Variable("v", 0);
-      if (prev !== null)
+      if (prev != null)
         new EqualityConstraint(prev, v, REQUIRED);
-      if (i === 0)
+      if (i == 0)
         first = v;
-      if (i === n)
+      if (i == n)
         last = v;
       prev = v;
     }
     new StayConstraint(last, STRONG_DEFAULT);
     let edit = new EditConstraint(first, PREFERRED);
     let plan = exports.planner.extractPlanFromConstraints(new core.List$(Constraint).from([edit]));
     for (let i = 0; dart.notNull(i) < 100; i = dart.notNull(i) + 1) {
       first.value = i;
       plan.execute();
-      if (last.value !== i) {
+      if (last.value != i) {
         core.print("Chain test failed:");
         core.print(`Expected last value to be ${i} but it was ${last.value}.`);
       }
     }
   }
   // Function projectionTest: (int) → void
   function projectionTest(n) {
     exports.planner = new Planner();
     let scale = new Variable("scale", 10);
     let offset = new Variable("offset", 1000);
     let src = null, dst = null;
     let dests = new core.List$(Variable).from([]);
     for (let i = 0; dart.notNull(i) < dart.notNull(n); i = dart.notNull(i) + 1) {
       src = new Variable("src", i);
       dst = new Variable("dst", i);
       dests.add(dst);
       new StayConstraint(src, NORMAL);
       new ScaleConstraint(src, scale, offset, dst, REQUIRED);
     }
     change(src, 17);
-    if (dst.value !== 1170)
+    if (dst.value != 1170)
       core.print("Projection 1 failed");
     change(dst, 1050);
-    if (src.value !== 5)
+    if (src.value != 5)
       core.print("Projection 2 failed");
     change(scale, 5);
     for (let i = 0; dart.notNull(i) < dart.notNull(n) - 1; i = dart.notNull(i) + 1) {
-      if (dests.get(i).value !== dart.notNull(i) * 5 + 1000)
+      if (dests.get(i).value != dart.notNull(i) * 5 + 1000)
         core.print("Projection 3 failed");
     }
     change(offset, 2000);
     for (let i = 0; dart.notNull(i) < dart.notNull(n) - 1; i = dart.notNull(i) + 1) {
-      if (dests.get(i).value !== dart.notNull(i) * 5 + 2000)
+      if (dests.get(i).value != dart.notNull(i) * 5 + 2000)
         core.print("Projection 4 failed");
     }
   }
   // Function change: (Variable, int) → void
   function change(v, newValue) {
     let edit = new EditConstraint(v, PREFERRED);
     let plan = exports.planner.extractPlanFromConstraints(new core.List$(EditConstraint).from([edit]));
     for (let i = 0; dart.notNull(i) < 10; i = dart.notNull(i) + 1) {
       v.value = newValue;
       plan.execute();
@@ skipping 22 matching lines @@
   exports.BinaryConstraint = BinaryConstraint;
   exports.ScaleConstraint = ScaleConstraint;
   exports.EqualityConstraint = EqualityConstraint;
   exports.Variable = Variable;
   exports.Planner = Planner;
   exports.Plan = Plan;
   exports.chainTest = chainTest;
   exports.projectionTest = projectionTest;
   exports.change = change;
 })(DeltaBlue || (DeltaBlue = {}));