Add helper methods for populating dateActionsCache/scandCache in the src/scripting_api/util.js file

Rather than inlining all of that code, by moving it into separate helper methods we can utilize `Map.prototype.getOrInsertComputed()` instead.

Also, make a couple of the existing class fields actually private.

src/scripting_api/util.js

@@ -17,13 +17,15 @@
 import { PDFObject } from "./pdf_object.js";
 
 class Util extends PDFObject {
+  #createDateActionsBound = this.#createDateActions.bind(this);
+
+  #createScandDataBound = this.#createScandData.bind(this);
+
   #dateActionsCache = null;
 
-  constructor(data) {
+  #scandCache = null;
-    super(data);
 
-    this._scandCache = new Map();
+  #months = [
-    this._months = [
     "January",
     "February",
     "March",
@@ -37,7 +39,8 @@ class Util extends PDFObject {
     "November",
     "December",
   ];
-    this._days = [
+
+  #days = [
     "Sunday",
     "Monday",
     "Tuesday",
@@ -46,8 +49,13 @@ class Util extends PDFObject {
     "Friday",
     "Saturday",
   ];
-    this.MILLISECONDS_IN_DAY = 86400000;
+
-    this.MILLISECONDS_IN_WEEK = 604800000;
+  MILLISECONDS_IN_DAY = 86400000;
+
+  MILLISECONDS_IN_WEEK = 604800000;
+
+  constructor(data) {
+    super(data);
 
     // used with crackURL
     this._externalCall = data.externalCall;
@@ -71,7 +79,7 @@ class Util extends PDFObject {
     let i = 0;
     return args[0].replaceAll(
       pattern,
-      function (match, nDecSep, cFlags, nWidth, nPrecision, cConvChar) {
+      function (_, nDecSep, cFlags, nWidth, nPrecision, cConvChar) {
         // cConvChar must be one of d, f, s, x
         if (
           cConvChar !== "d" &&
@@ -217,12 +225,12 @@ class Util extends PDFObject {
     }
 
     const handlers = {
-      mmmm: data => this._months[data.month],
+      mmmm: data => this.#months[data.month],
-      mmm: data => this._months[data.month].substring(0, 3),
+      mmm: data => this.#months[data.month].substring(0, 3),
       mm: data => (data.month + 1).toString().padStart(2, "0"),
       m: data => (data.month + 1).toString(),
-      dddd: data => this._days[data.dayOfWeek],
+      dddd: data => this.#days[data.dayOfWeek],
-      ddd: data => this._days[data.dayOfWeek].substring(0, 3),
+      ddd: data => this.#days[data.dayOfWeek].substring(0, 3),
       dd: data => data.day.toString().padStart(2, "0"),
       d: data => data.day.toString(),
       yyyy: data => data.year.toString().padStart(4, "0"),
@@ -251,7 +259,7 @@ class Util extends PDFObject {
 
     const patterns =
       /(mmmm|mmm|mm|m|dddd|ddd|dd|d|yyyy|yy|HH|H|hh|h|MM|M|ss|s|tt|t|\\.)/g;
-    return cFormat.replaceAll(patterns, function (match, pattern) {
+    return cFormat.replaceAll(patterns, function (_, pattern) {
       return pattern in handlers
         ? handlers[pattern](data)
         : pattern.charCodeAt(1);
@@ -337,16 +345,12 @@ class Util extends PDFObject {
     return buf.join("");
   }
 
-  #tryToGuessDate(cFormat, cDate) {
+  #createDateActions(cFormat) {
-    // We use the format to know the order of day, month, year, ...
+    const actions = [];
 
-    let actions = (this.#dateActionsCache ||= new Map()).get(cFormat);
-    if (!actions) {
-      actions = [];
-      this.#dateActionsCache.set(cFormat, actions);
     cFormat.replaceAll(
       /(d+)|(m+)|(y+)|(H+)|(M+)|(s+)/g,
-        function (_match, d, m, y, H, M, s) {
+      function (_, d, m, y, H, M, s) {
         if (d) {
           actions.push((n, data) => {
             if (n >= 1 && n <= 31) {
@@ -401,8 +405,18 @@ class Util extends PDFObject {
         return "";
       }
     );
+
+    return actions;
   }
 
+  #tryToGuessDate(cFormat, cDate) {
+    // We use the format to know the order of day, month, year, ...
+
+    const actions = (this.#dateActionsCache ??= new Map()).getOrInsertComputed(
+      cFormat,
+      this.#createDateActionsBound
+    );
+
     const number = /\d+/g;
     let i = 0;
     let array;
@@ -442,27 +456,9 @@ class Util extends PDFObject {
     return this._scand(cFormat, cDate);
   }
 
-  _scand(cFormat, cDate, strict = false) {
+  #createScandData(cFormat) {
-    if (typeof cDate !== "string") {
+    const months = this.#months,
-      return new Date(cDate);
+      days = this.#days;
-    }
-
-    if (cDate === "") {
-      return new Date();
-    }
-
-    switch (cFormat) {
-      case 0:
-        return this.scand("D:yyyymmddHHMMss", cDate);
-      case 1:
-        return this.scand("yyyy.mm.dd HH:MM:ss", cDate);
-      case 2:
-        return this.scand("m/d/yy h:MM:ss tt", cDate);
-    }
-
-    if (!this._scandCache.has(cFormat)) {
-      const months = this._months;
-      const days = this._days;
 
     const handlers = {
       mmmm: {
@@ -596,9 +592,7 @@ class Util extends PDFObject {
       /(mmmm|mmm|mm|m|dddd|ddd|dd|d|yyyy|yy|HH|H|hh|h|MM|M|ss|s|tt|t)/g;
     const actions = [];
 
-      const re = escapedFormat.replaceAll(
+    const re = escapedFormat.replaceAll(patterns, function (_, patternElement) {
-        patterns,
-        function (match, patternElement) {
       const { pattern, action } = handlers[patternElement];
       actions.push(action);
       // If the format is "Hm", then /\d{1,2}\d{1,2}/ is ambiguous so we use
@@ -606,14 +600,33 @@ class Util extends PDFObject {
       return pattern.includes(",")
         ? `(?=${pattern})\\${actions.length}`
         : pattern;
+    });
+
+    return [re, actions];
   }
+
+  _scand(cFormat, cDate, strict = false) {
+    if (typeof cDate !== "string") {
+      return new Date(cDate);
+    }
+    if (cDate === "") {
+      return new Date();
+    }
+
+    switch (cFormat) {
+      case 0:
+        return this.scand("D:yyyymmddHHMMss", cDate);
+      case 1:
+        return this.scand("yyyy.mm.dd HH:MM:ss", cDate);
+      case 2:
+        return this.scand("m/d/yy h:MM:ss tt", cDate);
+    }
+
+    const [re, actions] = (this.#scandCache ??= new Map()).getOrInsertComputed(
+      cFormat,
+      this.#createScandDataBound
     );
 
-      this._scandCache.set(cFormat, [re, actions]);
-    }
-
-    const [re, actions] = this._scandCache.get(cFormat);
-
     const matches = new RegExp(`^${re}$`, "g").exec(cDate);
     if (!matches || matches.length !== actions.length + 1) {
       return strict ? null : this.#tryToGuessDate(cFormat, cDate);