Use strict equality checks throughout codebase

Replaced all instances of '==' and '!=' with '===' and '!==' in canvas renderer, curves utility, and test files for consistency and to prevent type coercion issues.

Author: jonobr1

src/renderers/canvas.js

@@ -1,5 +1,10 @@
 import { Commands } from '../utils/path-commands.js';
-import { decomposeMatrix, mod, TWO_PI, getEffectiveStrokeWidth } from '../utils/math.js';
+import {
+  decomposeMatrix,
+  mod,
+  TWO_PI,
+  getEffectiveStrokeWidth,
+} from '../utils/math.js';
 import { Curve } from '../utils/curves.js';
 import { Events } from '../events.js';
 import { getRatio } from '../utils/device-pixel-ratio.js';
@@ -1253,6 +1258,11 @@ function svgAngle(ux, uy, vx, vy) {
 // Returns true if this is a non-transforming matrix
 function isDefaultMatrix(m) {
   return (
-    m[0] == 1 && m[3] == 0 && m[1] == 0 && m[4] == 1 && m[2] == 0 && m[5] == 0
+    m[0] === 1 &&
+    m[3] === 0 &&
+    m[1] === 0 &&
+    m[4] === 1 &&
+    m[2] === 0 &&
+    m[5] === 0
   );
 }

src/utils/curves.js

@@ -245,7 +245,7 @@ function getCurveBoundingBox(x1, y1, x2, y2, x3, y3, x4, y4) {
   let a, b, c, t, t1, t2, b2ac, sqrtb2ac;
 
   for (let i = 0; i < 2; ++i) {
-    if (i == 0) {
+    if (i === 0) {
       b = 6 * x1 - 12 * x2 + 6 * x3;
       a = -3 * x1 + 9 * x2 - 9 * x3 + 3 * x4;
       c = 3 * x2 - 3 * x1;

tests/src/utils.js

@@ -89,7 +89,7 @@
       xhr.open('GET', path, true);
 
       xhr.onreadystatechange = function (e) {
-        if (xhr.readyState != 4 || xhr.status != 200) {
+        if (xhr.readyState !== 4 || xhr.status !== 200) {
           return;
         }
 
@@ -113,7 +113,7 @@
       }
 
       xhr.onreadystatechange = function (e) {
-        if (xhr.readyState != 4 || xhr.status != 200) {
+        if (xhr.readyState !== 4 || xhr.status !== 200) {
           return;
         }
 

tests/suite/shapes.js

@@ -587,7 +587,7 @@ QUnit.test('Two.Rectangle', function (assert) {
 
   for (var i = 0; i < Two.Rectangle.Properties.length; i++) {
     var prop = Two.Rectangle.Properties[i];
-    var isOrigin = i == 2;
+    var isOrigin = i === 2;
     assert.equal(
       isOrigin ? JSON.stringify(path[prop].toObject()) : path[prop],
       properties[i],