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/*
This file is part of TALER
(C) 2016 GNUnet e.V.
TALER is free software; you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation; either version 3, or (at your option) any later version.
TALER is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
TALER; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
*/
/**
* Small helper functions that don't fit anywhere else.
*/
/**
* Imports.
*/
import { AmountJson } from "./amounts";
import * as Amounts from "./amounts";
/**
* Show an amount in a form suitable for the user.
* FIXME: In the future, this should consider currency-specific
* settings such as significant digits or currency symbols.
*/
export function amountToPretty(amount: AmountJson): string {
const x = amount.value + amount.fraction / Amounts.fractionalBase;
return `${x} ${amount.currency}`;
}
/**
* Canonicalize a base url, typically for the exchange.
*
* See http://api.taler.net/wallet.html#general
*/
export function canonicalizeBaseUrl(url: string) {
if (!url.startsWith("http") && !url.startsWith("https")) {
url = "https://" + url;
}
const x = new URL(url);
if (!x.pathname.endsWith("/")) {
x.pathname = x.pathname + "/";
}
x.search = "";
x.hash = "";
return x.href;
}
/**
* Convert object to JSON with canonical ordering of keys
* and whitespace omitted.
*/
export function canonicalJson(obj: any): string {
// Check for cycles, etc.
JSON.stringify(obj);
if (typeof obj === "string" || typeof obj === "number" || obj === null) {
return JSON.stringify(obj);
}
if (Array.isArray(obj)) {
const objs: string[] = obj.map((e) => canonicalJson(e));
return `[${objs.join(",")}]`;
}
const keys: string[] = [];
for (const key in obj) {
keys.push(key);
}
keys.sort();
let s = "{";
for (let i = 0; i < keys.length; i++) {
const key = keys[i];
s += JSON.stringify(key) + ":" + canonicalJson(obj[key]);
if (i !== keys.length - 1) {
s += ",";
}
}
return s + "}";
}
/**
* Check for deep equality of two objects.
* Only arrays, objects and primitives are supported.
*/
export function deepEquals(x: any, y: any): boolean {
if (x === y) {
return true;
}
if (Array.isArray(x) && x.length !== y.length) {
return false;
}
const p = Object.keys(x);
return (
Object.keys(y).every((i) => p.indexOf(i) !== -1) &&
p.every((i) => deepEquals(x[i], y[i]))
);
}
export function deepCopy(x: any): any {
// FIXME: this has many issues ...
return JSON.parse(JSON.stringify(x));
}
/**
* Map from a collection to a list or results and then
* concatenate the results.
*/
export function flatMap<T, U>(xs: T[], f: (x: T) => U[]): U[] {
return xs.reduce((acc: U[], next: T) => [...f(next), ...acc], []);
}
/**
* Compute the hash function of a JSON object.
*/
export function hash(val: any): number {
const str = canonicalJson(val);
// https://github.com/darkskyapp/string-hash
let h = 5381;
let i = str.length;
while (i) {
h = (h * 33) ^ str.charCodeAt(--i);
}
/* JavaScript does bitwise operations (like XOR, above) on 32-bit signed
* integers. Since we want the results to be always positive, convert the
* signed int to an unsigned by doing an unsigned bitshift. */
return h >>> 0;
}
/**
* Lexically compare two strings.
*/
export function strcmp(s1: string, s2: string): number {
if (s1 < s2) {
return -1;
}
if (s1 > s2) {
return 1;
}
return 0;
}
/**
* Run a function and return its result.
*
* Used as a nicer-looking way to do immediately invoked function
* expressions (IFFEs).
*/
export function runBlock<T>(f: () => T) {
return f();
}
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