add range js helpers

scripts/generate/templates/SafeCast.js

@@ -1,7 +1,8 @@
 const assert = require('assert');
 const format = require('../format-lines');
+const { range } = require('../../helpers');
 
-const LENGTHS = Array(31).fill().map((_, i) => (i + 1) * 8).reverse(); // 248 → 8 (in steps of 8)
+const LENGTHS = range(8, 256, 8).reverse(); // 248 → 8 (in steps of 8)
 
 // Returns the version of OpenZeppelin Contracts in which a particular function was introduced.
 // This is used in the docs for each function.

scripts/generate/templates/SafeCastMock.js

@@ -1,4 +1,7 @@
 const format = require('../format-lines');
+const { range } = require('../../helpers');
+
+const LENGTHS = range(8, 256, 8).reverse(); // 248 → 8 (in steps of 8)
 
 const header = `\
 pragma solidity ^0.8.0;
@@ -31,8 +34,6 @@ function toUint${length}(uint256 a) public pure returns (uint${length}) {
 `;
 
 // GENERATE
-const LENGTHS = Array(31).fill().map((_, i) => (i + 1) * 8).reverse(); // 248 → 8 (in steps of 8)
-
 module.exports = format(
   header,
   'contract SafeCastMock {',

scripts/helpers.js

@@ -0,0 +1,23 @@
+function chunk (array, size = 1) {
+    return Array.range(Math.ceil(array.length / size)).map(i => array.slice(i * size, i * size + size))
+}
+
+function range (start, stop = undefined, step = 1) {
+    if (!stop) { stop = start; start = 0; }
+    return start < stop ? Array(Math.ceil((stop - start) / step)).fill().map((_, i) => start + i * step) : [];
+}
+
+function unique (array, op = x => x) {
+    return array.filter((obj, i) => array.findIndex(entry => op(obj) === op(entry)) === i);
+}
+
+function zip (...args) {
+    return Array(Math.max(...args.map(arg => arg.length))).fill(null).map((_, i) => args.map(arg => arg[i]));
+}
+
+module.exports = {
+    chunk,
+    range,
+    unique,
+    zip,
+}

test/utils/math/SafeCast.test.js

@@ -1,6 +1,6 @@
 const { BN, expectRevert } = require('@openzeppelin/test-helpers');
-
 const { expect } = require('chai');
+const { range } = require('../../../scripts/helpers');
 
 const SafeCastMock = artifacts.require('SafeCastMock');
 
@@ -41,7 +41,7 @@ contract('SafeCast', async (accounts) => {
     });
   }
 
-  Array(31).fill().map((_, i) => (i + 1) * 8).forEach(bits => testToUint(bits));
+  range(8, 256, 8).forEach(bits => testToUint(bits));
 
   describe('toUint256', () => {
     const maxInt256 = new BN('2').pow(new BN(255)).subn(1);
@@ -129,7 +129,7 @@ contract('SafeCast', async (accounts) => {
     });
   }
 
-  Array(31).fill().map((_, i) => (i + 1) * 8).forEach(bits => testToInt(bits));
+  range(8, 256, 8).forEach(bits => testToInt(bits));
 
   describe('toInt256', () => {
     const maxUint256 = new BN('2').pow(new BN(256)).subn(1);