fix: tools/toFixed precision

lib/path.js

@@ -1,4 +1,4 @@
-import { removeLeadingZero, toFixed } from './svgo/tools.js';
+import { removeLeadingZero, toFixedStr } from './svgo/tools.js';
 
 /**
  * @typedef {import('./types.js').PathDataItem} PathDataItem
@@ -239,23 +239,6 @@ export const parsePathData = (string) => {
   return pathData;
 };
 
-/**
- * @type {(number: number, precision?: number) => {
- *   roundedStr: string,
- *   rounded: number
- * }}
- */
-const roundAndStringify = (number, precision) => {
-  if (precision != null) {
-    number = toFixed(number, precision);
-  }
-
-  return {
-    roundedStr: removeLeadingZero(number),
-    rounded: number,
-  };
-};
-
 /**
  * Elliptical arc large-arc and sweep flags are rendered with spaces
  * because many non-browser environments are not able to parse such paths
@@ -272,30 +255,38 @@ const stringifyArgs = (command, args, precision, disableSpaceAfterFlags) => {
   let previous;
 
   for (let i = 0; i < args.length; i++) {
-    const { roundedStr, rounded } = roundAndStringify(args[i], precision);
-    if (
+    let number = args[i];
+    if (precision != null) {
+      number = toFixedStr(number.toString(), precision);
+    }
+    const roundedStr = removeLeadingZero(number);
+
+    const skipSpace = (
+      // avoid space before first
+      i === 0
+    ) || (
+      // avoid space before negative numbers
+      number < 0
+    ) || (
+      // consider combined arcs
       disableSpaceAfterFlags &&
       (command === 'A' || command === 'a') &&
-      // consider combined arcs
       (i % 7 === 4 || i % 7 === 5)
-    ) {
-      result += roundedStr;
-    } else if (i === 0 || rounded < 0) {
-      // avoid space before first and negative numbers
-      result += roundedStr;
-    } else if (
-      !Number.isInteger(previous) &&
-      rounded != 0 &&
-      rounded < 1 &&
-      rounded > -1
-    ) {
+    ) || (
       // remove space before decimal with zero whole
-      // only when previous number is also decimal
-      result += roundedStr;
-    } else {
-      result += ` ${roundedStr}`;
+      previous % 1 && // only when previous number is also decimal
+      number != 0 &&
+      number < 1 &&
+      number > -1
+    );
+
+    if (!skipSpace) {
+      result += ' ';
     }
-    previous = rounded;
+
+    result += roundedStr;
+
+    previous = number;
   }
 
   return result;

lib/svgo/tools.js

@@ -226,13 +226,34 @@ export const findReferences = (attribute, value) => {
 
 /**
  * Does the same as {@link Number.toFixed} but without casting
- * the return value to a string.
+ * the return value to a string and correctly fix numbers
+ * like 21.0565 to 21.057 when precision is 3.
  *
  * @param {number} num
  * @param {number} precision
  * @returns {number}
  */
 export const toFixed = (num, precision) => {
+  if (precision > 17 || num % 1 == 0) return num;
+
   const pow = 10 ** precision;
   return Math.round(num * pow) / pow;
 };
+
+/**
+ * Does the same as {@link Number.toFixed} and correctly
+ * fix numbers like 2.5845 to 2.585 when precision is 3.
+ *
+ * @param {string} numStr
+ * @param {number} precision
+ * @returns {string}
+ */
+export const toFixedStr = (numStr, precision) => {
+  const pow = 10 ** precision;
+  const fixed = Math.round(numStr * pow) / pow;
+  const result = fixed.toString();
+
+  // prevent returning more digits than originally given
+  const isRegression = result.length > numStr.length;
+  return isRegression ? numStr : result;
+};

plugins/applyTransforms.js

@@ -12,7 +12,7 @@ import {
 import { referencesProps, attrsGroupsDefaults } from './_collections.js';
 import { collectStylesheet, computeStyle } from '../lib/style.js';
 
-import { removeLeadingZero, includesUrlReference } from '../lib/svgo/tools.js';
+import { removeLeadingZero, includesUrlReference, toFixed } from '../lib/svgo/tools.js';
 
 /**
  * @typedef {PathDataItem[]} PathData
@@ -92,11 +92,8 @@ export const applyTransforms = (root, params) => {
           return;
         }
 
-        const scale = Number(
-          Math.hypot(matrix.data[0], matrix.data[1]).toFixed(
-            transformPrecision,
-          ),
-        );
+        const scale = toFixed(Math.hypot(matrix.data[0], matrix.data[1]),
+          transformPrecision);
 
         if (stroke && stroke != 'none') {
           if (!params.applyTransformsStroked) {

plugins/cleanupListOfValues.js

@@ -1,4 +1,4 @@
-import { removeLeadingZero } from '../lib/svgo/tools.js';
+import { removeLeadingZero, toFixedStr } from '../lib/svgo/tools.js';
 
 export const name = 'cleanupListOfValues';
 export const description = 'rounds list of values to the fixed precision';
@@ -52,8 +52,7 @@ export const fn = (_root, params) => {
 
       // if attribute value matches regNumericValues
       if (match) {
-        // round it to the fixed precision
-        let num = Number(Number(match[1]).toFixed(floatPrecision));
+        let strNum = match[1];
         /**
          * @type {any}
          */
@@ -65,22 +64,19 @@ export const fn = (_root, params) => {
 
         // convert absolute values to pixels
         if (convertToPx && units && units in absoluteLengths) {
-          const pxNum = Number(
-            (absoluteLengths[units] * Number(match[1])).toFixed(floatPrecision),
-          );
+          const pxNum = (absoluteLengths[units] * strNum).toString();
 
-          if (pxNum.toString().length < match[0].length) {
-            num = pxNum;
+          if (pxNum.length < match[0].length) {
+            strNum = pxNum;
             units = 'px';
           }
         }
 
+        // round it to the fixed precision
+        let str = toFixedStr(strNum, floatPrecision);
         // and remove leading zero
-        let str;
         if (leadingZero) {
-          str = removeLeadingZero(num);
-        } else {
-          str = num.toString();
+          str = removeLeadingZero(str);
         }
 
         // remove default 'px' units

plugins/cleanupNumericValues.js

@@ -1,4 +1,4 @@
-import { removeLeadingZero } from '../lib/svgo/tools.js';
+import { removeLeadingZero, toFixedStr } from '../lib/svgo/tools.js';
 
 export const name = 'cleanupNumericValues';
 export const description =
@@ -43,7 +43,7 @@ export const fn = (_root, params) => {
               const num = Number(value);
               return Number.isNaN(num)
                 ? value
-                : Number(num.toFixed(floatPrecision));
+                : toFixedStr(value, floatPrecision);
             })
             .join(' ');
         }
@@ -59,7 +59,7 @@ export const fn = (_root, params) => {
           // if attribute value matches regNumericValues
           if (match) {
             // round it to the fixed precision
-            let num = Number(Number(match[1]).toFixed(floatPrecision));
+            let strNum = match[1];
             /**
              * @type {any}
              */
@@ -71,23 +71,18 @@ export const fn = (_root, params) => {
 
             // convert absolute values to pixels
             if (convertToPx && units !== '' && units in absoluteLengths) {
-              const pxNum = Number(
-                (absoluteLengths[units] * Number(match[1])).toFixed(
-                  floatPrecision,
-                ),
-              );
-              if (pxNum.toString().length < match[0].length) {
-                num = pxNum;
+              const pxNum = (absoluteLengths[units] * strNum).toString();
+              if (pxNum.length < match[0].length) {
+                strNum = pxNum;
                 units = 'px';
               }
             }
 
+            // round it to the fixed precision
+            let str = toFixedStr(strNum, floatPrecision);
             // and remove leading zero
-            let str;
             if (leadingZero) {
-              str = removeLeadingZero(num);
-            } else {
-              str = num.toString();
+              str = removeLeadingZero(str);
             }
 
             // remove default 'px' units