Default pivots from which partitions can be derived

src/pivots/index.js

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+// ['0', (...), '9']
+const numbers = Array.from({ length: 10 }, (_, i) => String.fromCharCode(48 + i));
+
+// ['a', (...), 'z']
+const alphabet = Array.from({ length: 26 }, (_, i) => String.fromCharCode(97 + i));
+
+/*
+  azExpand('a') => [
+    'aa', 'ab', 'ac', 'ad', 'ae',
+    'af', 'ag', 'ah', 'ai', 'aj',
+    'ak', 'al', 'am', 'an', 'ao',
+    'ap', 'aq', 'ar', 'as', 'at',
+    'au', 'av', 'aw', 'ax', 'ay',
+    'az'
+  ]
+*/
+function azExpand(prefix) {
+  return [
+    ...alphabet.map(c => `${prefix}${c}`)
+  ];
+}
+
+// ['a', (...), 'zzz']
+const atozzz = alphabet.reduce((acc, a) => {
+  acc.push(a);                  // ['a', (...)
+
+  azExpand(a)
+    .forEach(aa => {
+      acc.push(...azExpand(aa)) //  (...) aaa', 'aab', 'aac']
+    });
+
+  return acc;
+}, []);
+
+const allPivots = [
+  null,
+  /* 0 – 9 */
+  ...numbers,
+  '@!',
+  /* @0 – @9 */
+  ...numbers.map(c => `@${c}`),
+  '@_',
+  //
+  // TODO (cjr) must partition @ali__@alj
+  // [@ali, @alicn, @alifd, @alifd/theme-{???}, @aligov, @aliwind, @alj]
+  //
+  /* @a[a-z] - @z[a-z] */
+  ...atozzz.map(cc => `@${cc}`),
+  //
+  // TODO (cjr) must partition nod_noe
+  // entire `node-*` package namespace
+  //
+  '@~',
+  'A',
+  'Z',
+  ...atozzz,
+  null
+]
+
+const pivots = allPivots;
+
+export {
+  pivots
+}

src/pivots/package.json

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+{
+  "name": "@_all_docs/partition",
+  "version": "0.1.0",
+  "description": "Default pivots from which _all_docs partitions are derived",
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/indexzero/_all_docs.git",
+    "directory": "src/partition"
+  },
+  "author": "Charlie Robbins <npm@charlie.dev>",
+  "license": "Apache-2.0"
+}