Enable the prefer-exponentiation-operator ESLint rule

Please see https://eslint.org/docs/rules/prefer-exponentiation-operator for additional information.

.eslintrc

@@ -158,6 +158,7 @@
       },
     ],
     "no-unneeded-ternary": "error",
+    "prefer-exponentiation-operator": "error",
     "spaced-comment": ["error", "always", {
       "block": {
         "balanced": true,

src/core/colorspace.js

@@ -889,14 +889,14 @@ const CalGrayCS = (function CalGrayCSClosure() {
     // A represents a gray component of a calibrated gray space.
     // A <---> AG in the spec
     const A = src[srcOffset] * scale;
-    const AG = Math.pow(A, cs.G);
+    const AG = A ** cs.G;
 
     // Computes L as per spec. ( = cs.YW * AG )
     // Except if other than default BlackPoint values are used.
     const L = cs.YW * AG;
     // http://www.poynton.com/notes/colour_and_gamma/ColorFAQ.html, Ch 4.
     // Convert values to rgb range [0, 255].
-    const val = Math.max(295.8 * Math.pow(L, 0.333333333333333333) - 40.8, 0);
+    const val = Math.max(295.8 * L ** 0.333333333333333333 - 40.8, 0);
     dest[destOffset] = val;
     dest[destOffset + 1] = val;
     dest[destOffset + 2] = val;
@@ -1026,7 +1026,7 @@ const CalRGBCS = (function CalRGBCSClosure() {
   const tempConvertMatrix1 = new Float32Array(3);
   const tempConvertMatrix2 = new Float32Array(3);
 
-  const DECODE_L_CONSTANT = Math.pow((8 + 16) / 116, 3) / 8.0;
+  const DECODE_L_CONSTANT = ((8 + 16) / 116) ** 3 / 8.0;
 
   function matrixProduct(a, b, result) {
     result[0] = a[0] * b[0] + a[1] * b[1] + a[2] * b[2];
@@ -1055,7 +1055,7 @@ const CalRGBCS = (function CalRGBCSClosure() {
     if (color <= 0.0031308) {
       return adjustToRange(0, 1, 12.92 * color);
     }
-    return adjustToRange(0, 1, (1 + 0.055) * Math.pow(color, 1 / 2.4) - 0.055);
+    return adjustToRange(0, 1, (1 + 0.055) * color ** (1 / 2.4) - 0.055);
   }
 
   function adjustToRange(min, max, value) {
@@ -1067,7 +1067,7 @@ const CalRGBCS = (function CalRGBCSClosure() {
       return -decodeL(-L);
     }
     if (L > 8.0) {
-      return Math.pow((L + 16) / 116, 3);
+      return ((L + 16) / 116) ** 3;
     }
     return L * DECODE_L_CONSTANT;
   }
@@ -1154,9 +1154,9 @@ const CalRGBCS = (function CalRGBCSClosure() {
     // A <---> AGR in the spec
     // B <---> BGG in the spec
     // C <---> CGB in the spec
-    const AGR = Math.pow(A, cs.GR);
+    const AGR = A ** cs.GR;
-    const BGG = Math.pow(B, cs.GG);
+    const BGG = B ** cs.GG;
-    const CGB = Math.pow(C, cs.GB);
+    const CGB = C ** cs.GB;
 
     // Computes intermediate variables L, M, N as per spec.
     // To decode X, Y, Z values map L, M, N directly to them.

src/core/fonts.js

@@ -1166,7 +1166,7 @@ var Font = (function FontClosure() {
   }
 
   function createPostTable(properties) {
-    var angle = Math.floor(properties.italicAngle * Math.pow(2, 16));
+    var angle = Math.floor(properties.italicAngle * 2 ** 16);
     return (
       "\x00\x03\x00\x00" + // Version number
       string32(angle) + // italicAngle

src/core/function.js

@@ -83,7 +83,7 @@ var PDFFunction = (function PDFFunctionClosure() {
       var codeSize = 0;
       var codeBuf = 0;
       // 32 is a valid bps so shifting won't work
-      var sampleMul = 1.0 / (Math.pow(2.0, bps) - 1);
+      var sampleMul = 1.0 / (2.0 ** bps - 1);
 
       var strBytes = stream.getBytes((length * bps + 7) / 8);
       var strIdx = 0;
@@ -227,7 +227,7 @@ var PDFFunction = (function PDFFunctionClosure() {
         samples,
         size,
         outputSize,
-        Math.pow(2, bps) - 1,
+        2 ** bps - 1,
         range,
       ];
     },
@@ -358,7 +358,7 @@ var PDFFunction = (function PDFFunctionClosure() {
         dest,
         destOffset
       ) {
-        var x = n === 1 ? src[srcOffset] : Math.pow(src[srcOffset], n);
+        var x = n === 1 ? src[srcOffset] : src[srcOffset] ** n;
 
         for (var j = 0; j < length; ++j) {
           dest[destOffset + j] = c0[j] + x * diff[j];
@@ -726,7 +726,7 @@ var PostScriptEvaluator = (function PostScriptEvaluatorClosure() {
           case "exp":
             b = stack.pop();
             a = stack.pop();
-            stack.push(Math.pow(a, b));
+            stack.push(a ** b);
             break;
           case "false":
             stack.push(false);

src/core/jpx.js

@@ -1434,7 +1434,7 @@ var JpxImage = (function JpxImageClosure() {
         // calculate quantization coefficient (Section E.1.1.1)
         var delta = reversible
           ? 1
-          : Math.pow(2, precision + gainLog2 - epsilon) * (1 + mu / 2048);
+          : 2 ** (precision + gainLog2 - epsilon) * (1 + mu / 2048);
         var mb = guardBits + epsilon - 1;
 
         // In the first resolution level, copyCoefficients will fill the

src/core/parser.js

@@ -948,7 +948,7 @@ class Lexer {
       baseValue /= divideBy;
     }
     if (eNotation) {
-      baseValue *= Math.pow(10, powerValueSign * powerValue);
+      baseValue *= 10 ** (powerValueSign * powerValue);
     }
     return sign * baseValue;
   }