refactor: improve performance of stringifyPathData

lib/path.js

@@ -243,15 +243,21 @@ const parsePathData = (string) => {
 exports.parsePathData = parsePathData;
 
 /**
- * @type {(number: number, precision?: number) => string}
+ * @type {(number: number, precision?: number) => {
+ * roundedStr: string,
+ * rounded: number
+ * }}
  */
-const stringifyNumber = (number, precision) => {
+const roundAndStringify = (number, precision) => {
  if (precision != null) {
  const ratio = 10 ** precision;
  number = Math.round(number * ratio) / ratio;
  }
- // remove zero whole from decimal number
- return removeLeadingZero(number);
+
+ return {
+ roundedStr: removeLeadingZero(number),
+ rounded: number,
+ };
 };
 
 /**
@@ -267,29 +273,35 @@ const stringifyNumber = (number, precision) => {
  */
 const stringifyArgs = (command, args, precision, disableSpaceAfterFlags) => {
  let result = '';
- let prev = '';
- for (let i = 0; i < args.length; i += 1) {
-  const number = args[i];
- const numberString = stringifyNumber(number, precision);
+ let previous;
+
+ for (let i = 0; i < args.length; i++) {
+ const { roundedStr, rounded } = roundAndStringify(args[i], precision);
  if (
  disableSpaceAfterFlags &&
  (command === 'A' || command === 'a') &&
  // consider combined arcs
  (i % 7 === 4 || i % 7 === 5)
  ) {
- result += numberString;
- } else if (i === 0 || numberString.startsWith('-')) {
+ result += roundedStr;
+ } else if (i === 0 || rounded < 0) {
  // avoid space before first and negative numbers
- result += numberString;
- } else if (prev.includes('.') && numberString.startsWith('.')) {
+ 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 += numberString;
+ result += roundedStr;
  } else {
- result += ` ${numberString}`;
+ result += ` ${roundedStr}`;
  }
- prev = numberString;
+ previous = rounded;
  }
+
  return result;
 };
 
@@ -302,48 +314,68 @@ const stringifyArgs = (command, args, precision, disableSpaceAfterFlags) => {
  */
 
 /**
- * @type {(options: StringifyPathDataOptions) => string}
+ * @param {StringifyPathDataOptions} options
+ * @returns {string}
  */
 const stringifyPathData = ({ pathData, precision, disableSpaceAfterFlags }) => {
- // combine sequence of the same commands
- let combined = [];
- for (let i = 0; i < pathData.length; i += 1) {
+ if (pathData.length === 1) {
+ const { command, args } = pathData[0];
+ return (
+ command + stringifyArgs(command, args, precision, disableSpaceAfterFlags)
+ );
+ }
+
+ let result = '';
+ let prev = { ...pathData[0] };
+
+ // match leading moveto with following lineto
+ if (pathData[1].command === 'L') {
+ prev.command = 'M';
+ } else if (pathData[1].command === 'l') {
+ prev.command = 'm';
+ }
+
+ for (let i = 1; i < pathData.length; i++) {
  const { command, args } = pathData[i];
- if (i === 0) {
- combined.push({ command, args });
- } else {
- /**
- * @type {PathDataItem}
- */
- const last = combined[combined.length - 1];
- // match leading moveto with following lineto
- if (i === 1) {
- if (command === 'L') {
- last.command = 'M';
- }
- if (command === 'l') {
- last.command = 'm';
- }
+ if (
+ (prev.command === command &&
+ prev.command !== 'M' &&
+ prev.command !== 'm') ||
+ // combine matching moveto and lineto sequences
+ (prev.command === 'M' && command === 'L') ||
+ (prev.command === 'm' && command === 'l')
+ ) {
+ prev.args = [...prev.args, ...args];
+ if (i === pathData.length - 1) {
+ result +=
+ prev.command +
+ stringifyArgs(
+ prev.command,
+ prev.args,
+ precision,
+ disableSpaceAfterFlags,
+ );
  }
- if (
- (last.command === command &&
- last.command !== 'M' &&
- last.command !== 'm') ||
- // combine matching moveto and lineto sequences
- (last.command === 'M' && command === 'L') ||
- (last.command === 'm' && command === 'l')
- ) {
- last.args = [...last.args, ...args];
+ } else {
+ result +=
+ prev.command +
+ stringifyArgs(
+ prev.command,
+ prev.args,
+ precision,
+ disableSpaceAfterFlags,
+ );
+
+ if (i === pathData.length - 1) {
+ result +=
+ command +
+ stringifyArgs(command, args, precision, disableSpaceAfterFlags);
  } else {
- combined.push({ command, args });
+ prev = { command, args };
  }
  }
  }
- let result = '';
- for (const { command, args } of combined) {
- result +=
- command + stringifyArgs(command, args, precision, disableSpaceAfterFlags);
- }
+
  return result;
 };
 exports.stringifyPathData = stringifyPathData;

lib/svgo/tools.js

@@ -124,23 +124,24 @@ exports.cleanupOutData = (data, params, command) => {
 /**
  * Remove floating-point numbers leading zero.
  *
+ * @param {number} value
+ * @returns {string}
  * @example
  * 0.5 → .5
- *
- * @example
  * -0.5 → -.5
- *
- * @type {(num: number) => string}
  */
-const removeLeadingZero = (num) => {
- var strNum = num.toString();
+const removeLeadingZero = (value) => {
+ const strValue = value.toString();
 
- if (0 < num && num < 1 && strNum.charAt(0) === '0') {
- strNum = strNum.slice(1);
- } else if (-1 < num && num < 0 && strNum.charAt(1) === '0') {
- strNum = strNum.charAt(0) + strNum.slice(2);
+ if (0 < value && value < 1 && strValue.startsWith('0')) {
+ return strValue.slice(1);
  }
- return strNum;
+
+ if (-1 < value && value < 0 && strValue[1] === '0') {
+ return strValue[0] + strValue.slice(2);
+ }
+
+ return strValue;
 };
 exports.removeLeadingZero = removeLeadingZero;