@polkadot/util
Version:
A collection of useful utilities for @polkadot
50 lines (49 loc) • 1.46 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.u8aCmp = u8aCmp;
const toU8a_js_1 = require("./toU8a.js");
/**
* @name u8aCmp
* @summary Compares two Uint8Arrays for sorting.
* @description
* For `UInt8Array` (or hex string) input values returning -1, 0 or +1
* @example
* <BR>
*
* ```javascript
* import { u8aCmp } from '@polkadot/util';
*
* u8aCmp(new Uint8Array([0x67, 0x65]), new Uint8Array([0x68, 0x65])); // -1
* u8aCmp(new Uint8Array([0x68, 0x65]), new Uint8Array([0x68, 0x65])); // 0
* u8aCmp(new Uint8Array([0x69, 0x65]), new Uint8Array([0x68, 0x65])); // +1
* ```
*/
function u8aCmp(a, b) {
const u8aa = (0, toU8a_js_1.u8aToU8a)(a);
const u8ab = (0, toU8a_js_1.u8aToU8a)(b);
let i = 0;
while (true) {
const overA = i >= u8aa.length;
const overB = i >= u8ab.length;
if (overA && overB) {
// both ends reached
return 0;
}
else if (overA) {
// a has no more data, b has data
return -1;
}
else if (overB) {
// b has no more data, a has data
return 1;
}
else if (u8aa[i] !== u8ab[i]) {
// the number in this index doesn't match
// (we don't use u8aa[i] - u8ab[i] since that doesn't match with localeCompare)
return u8aa[i] > u8ab[i]
? 1
: -1;
}
i++;
}
}