♻️ refactor: Simplify API.

Author: make-github-pseudonymous-again

README.md

@@ -12,23 +12,25 @@ See [docs](https://string-data-structure.github.io/fibonacci-string/index.html).
 > [regenerator-runtime/runtime](https://www.npmjs.com/package/regenerator-runtime).
 
 ```js
-import {build} from '@string-data-structure/fibonacci-string';
-
-const f = build({iadd: (x, y) => x+y, zero: () => 1, one: () => 1});
-
-f(0); // 1
-f(1); // 0
-f(2); // 1
-f(3); // 1
-f(4); // 0
-f(5); // 1
-f(6); // 0
-f(7); // 1
-f(8); // 1
-f(9); // 0
-
-const fn = build({iadd: (x, y) => x+y, zero: () => 1n, one: () => 1n});
-f(4802349082340928340983n); // 0
+import {makeIndex, query} from '@string-data-structure/fibonacci-string';
+
+const F = makeIndex({iadd: (x, y) => x+y, zero: () => 1, one: () => 2}, 10);
+
+query(F, 0); // 0
+query(F, 1); // 1
+query(F, 2); // 0
+query(F, 3); // 0
+query(F, 4); // 1
+query(F, 5); // 0
+query(F, 6); // 1
+query(F, 7); // 0
+query(F, 8); // 0
+query(F, 9); // 1
+query(F, 10); // 0
+
+const Fn = makeIndex({iadd: (x, y) => x+y, zero: () => 1n, one: () => 2n}, 10n**100n);
+query(Fn, 4802349082340928340983n); // 1n
+query(Fn, 123456748023490823409283409834802349082340928340983n); // 0n
 ```
 
 [![License](https://img.shields.io/github/license/string-data-structure/fibonacci-string.svg)](https://raw.githubusercontent.com/string-data-structure/fibonacci-string/main/LICENSE)

src/index.js

@@ -1,3 +1,3 @@
-export {default as build} from './build.js';
+export {default as makeIndex} from './makeIndex.js';
 export {default as gen} from './gen.js';
 export {default as query} from './query.js';

src/build.js renamed to src/makeIndex.js

@@ -4,15 +4,15 @@ import {le} from '@functional-abstraction/predicate';
 import gen from './gen.js';
 
 /**
- * Build.
+ * Make index up to at least a given query position.
  *
  * @param {Object}
  * @param {number|bigint} n
  * @return {number[]|bigint[]}
  */
-const build = ({zero, one, iadd}, n) => {
+const makeIndex = ({zero, one, iadd}, n) => {
 	const g = gen(iadd, zero(), one());
 	return Array.from(takewhile(le(n), g));
 };
 
-export default build;
+export default makeIndex;

src/query.js

@@ -1,36 +1,28 @@
 import assert from 'node:assert';
-import build from './build.js';
 
 /**
  * Query ϕ[i].
  *
- * @param {Object} type
- * @param {number[]|bigint[]} array
+ * @param {number[]|bigint[]} F
  * @param {number|bigint} i
  * @return {number|bigint}
  */
-const query = (type, array, i) => {
+const query = (F, i) => {
 	assert(typeof i === 'bigint' || (Number.isInteger(i) && i >= 0));
 	assert(typeof i !== 'bigint' || i >= 0n);
-	assert(array || type);
-	const F = array ?? build(type, i);
 	let n_1 = F.length - 1;
 	const zero = n_1 === -1 ? i : F[0] - F[0];
-	assert(array || i === zero || i >= F[n_1]);
 	// eslint-disable-next-line no-constant-condition
 	while (true) {
 		assert(i >= zero);
-		assert(array || n_1 + 1 === F.length);
 		if (n_1 <= 0) return i;
 		assert(n_1 + 1 >= 2);
 		assert(i < F[n_1] + F[n_1 - 1]); // Equivalent to i < F[n] = F[n_1 + 1]
 		if (i >= F[n_1]) {
 			i -= F[n_1];
 			--n_1;
-			if (F !== array) F.pop();
 		}
 
-		if (F !== array) F.pop();
 		--n_1;
 	}
 };

test/src/_fixtures.js

@@ -39,7 +39,7 @@ export const gs = function* ({a, b}, n) {
 
 	const F = Array.from(take(gen(iadd, a.length, a.length + b.length), n - 1));
 	const Fn = F.pop();
-	for (const i of range(Fn)) yield query(undefined, F, i);
+	for (const i of range(Fn)) yield query(F, i);
 };
 
 export const makeSymbol = ({a, b}) => {

test/src/examples.js

@@ -0,0 +1,35 @@
+import test from 'ava';
+
+import {makeIndex, query} from '../../src/index.js';
+
+test('README.md (Number)', (t) => {
+	const F = makeIndex({iadd: (x, y) => x + y, zero: () => 1, one: () => 2}, 10);
+
+	t.is(query(F, 0), 0);
+	t.is(query(F, 1), 1);
+	t.is(query(F, 2), 0);
+	t.is(query(F, 3), 0);
+	t.is(query(F, 4), 1);
+	t.is(query(F, 5), 0);
+	t.is(query(F, 6), 1);
+	t.is(query(F, 7), 0);
+	t.is(query(F, 8), 0);
+	t.is(query(F, 9), 1);
+	t.is(query(F, 10), 0);
+});
+
+test('README.md (BigInt)', (t) => {
+	const Fn = makeIndex(
+		{iadd: (x, y) => x + y, zero: () => 1n, one: () => 2n},
+		10n ** 100n,
+	);
+
+	t.is(query(Fn, 4_802_349_082_340_928_340_983n), 1n);
+	t.is(
+		query(
+			Fn,
+			123_456_748_023_490_823_409_283_409_834_802_349_082_340_928_340_983n,
+		),
+		0n,
+	);
+});

test/src/query.js

@@ -2,14 +2,15 @@ import test from 'ava';
 
 import {enumerate} from '@iterable-iterator/zip';
 
-import {query} from '../../src/index.js';
+import {query, makeIndex} from '../../src/index.js';
 
 import {makeSymbol, type, typen, repr} from './_fixtures.js';
 
 const symbol = makeSymbol({a: 'a', b: 'b'});
 
 const macro = (t, type, i, expected) => {
-	t.is(symbol(query(type, undefined, i)), expected);
+	const F = makeIndex(type, i);
+	t.is(symbol(query(F, i)), expected);
 };
 
 macro.title = (title, _, i, expected) =>