Add fontExtensions configuration option. (mathjax/MathJax#3410)

components/mjs/output/util.js

@@ -2,9 +2,29 @@ import {combineDefaults, combineWithMathJax} from '#js/components/global.js';
 import {Package} from '#js/components/package.js';
 import {hasWindow} from '#js/util/context.js';
 
-export const FONTPATH = hasWindow ?
-                        'https://cdn.jsdelivr.net/npm/@mathjax/%%FONT%%-font':
-                        '@mathjax/%%FONT%%-font';
+export const FONTPATH = hasWindow
+  ? 'https://cdn.jsdelivr.net/npm/@mathjax/%%FONT%%-font'
+  : '@mathjax/%%FONT%%-font';
+
+export function configFont(font, jax, config, extension = '') {
+  const path = (config.fontPath || (FONTPATH + extension));
+  const name = (font.match(/^[a-z]+:/) ? (font.match(/[^/:\\]*$/) || [jax])[0] : font);
+  combineDefaults(MathJax.config.loader, 'paths', {
+    [name+extension]: (name === font ? path.replace(/%%FONT%%/g, font) : font)
+  });
+  return `[${name}${extension}]`;
+}
+
+export function configExtensions(jax, config) {
+  const extensions = [];
+  for (const name of (config.fontExtensions || [])) {
+    const font = configFont(name, jax, config, '-extension');
+    const module = `${font}/${jax}`
+    extensions.push(module);
+  }
+  return extensions;
+}
+
 export const OutputUtil = {
   config(jax, jaxClass, defaultFont, fontClass) {
 
@@ -20,15 +40,15 @@ export const OutputUtil = {
       }
 
       if (font.charAt(0) !== '[') {
-        const path = (config.fontPath || FONTPATH);
-        const name = (font.match(/^[a-z]+:/) ? (font.match(/[^/:\\]*$/) || [jax])[0] : font);
-        combineDefaults(MathJax.config.loader, 'paths', {
-          [name]: (name === font ? path.replace(/%%FONT%%/g, font) : font)
-        });
-        font = `[${name}]`;
+        font = configFont(font, jax, config);
       }
       const name = font.substring(1, font.length - 1);
 
+      const extensions = configExtensions(jax, config);
+      if (extensions.length) {
+        MathJax.loader.addPackageData(`${font}/${jax}`, {extraLoads: extensions});
+      }
+
       if (name !== defaultFont || !fontClass) {
 
         MathJax.loader.addPackageData(`output/${jax}`, {extraLoads: [`${font}/${jax}`]});

ts/output/common.ts

@@ -144,6 +144,7 @@ export abstract class CommonOutputJax<
       LinebreakVisitor: null,      // The LinebreakVisitor to use
     },
     font: '',                      // the font component to load
+    fontExtensions: [],            // the font extensions to load
     htmlHDW: 'auto',               // 'use', 'force', or 'ignore' data-mjx-hdw attributes
     wrapperFactory: null,          // The wrapper factory to use
     fontData: null,                // The FontData object to use
@@ -183,6 +184,15 @@ export abstract class CommonOutputJax<
     },
   };
 
+  /**
+   * The font to use for generic extensions
+   */
+  public static genericFont: FontDataClass<
+    CharOptions,
+    VariantData<CharOptions>,
+    DelimiterData
+  >;
+
   /**
    * Used for collecting styles needed for the output jax
    */
@@ -305,6 +315,8 @@ export abstract class CommonOutputJax<
     this.styleJson = this.options.styleJson || new StyleJsonSheet();
     this.font = font || new fontClass(fontOptions);
     this.font.setOptions({ mathmlSpacing: this.options.mathmlSpacing });
+    /* prettier-ignore */
+    (this.constructor as typeof CommonOutputJax<N, T, D, WW, WF, WC, CC, VV, DD, FD, FC>).genericFont = fontClass;
     this.unknownCache = new Map();
     const linebreaks = (this.options.linebreaks.LinebreakVisitor ||
       LinebreakVisitor) as typeof Linebreaks;
@@ -349,9 +361,17 @@ export abstract class CommonOutputJax<
    * @override
    */
   public typeset(math: MathItem<N, T, D>, html: MathDocument<N, T, D>) {
+    /* prettier-ignore */
+    const CLASS = (this.constructor as typeof CommonOutputJax<N, T, D, WW, WF, WC, CC, VV, DD, FD, FC>);
+    const generic = CLASS.genericFont;
+    CLASS.genericFont = this.font.constructor as FontDataClass<CC, VV, DD>;
     this.setDocument(html);
     const node = this.createNode();
-    this.toDOM(math, node, html);
+    try {
+      this.toDOM(math, node, html);
+    } finally {
+      CLASS.genericFont = generic;
+    }
     return node;
   }