Web utils

A heavily-optimized web utility library.

CSP

Content-Security-Policy header parser.

import { csp } from "@bit-js/web-utils";

// Parse options to header value
csp.parse(options);

// No options
csp.parse(); // "default-src 'self'"

Available options are:

export interface Options {
  baseURI?: string | string[];
  reportTo?: string;

  sandbox?: string | true;
  upgradeInsecureRequests?: boolean;

  frameAncestors?: string | string[];
  formAction?: string | string[];

  sources?: {
    default?: string | string[];

    child?: string | string[];
    connect?: string | string[];
    font?: string | string[];
    image?: string | string[];
    media?: string | string[];
    object?: string | string[];
    manifest?: string | string[];
    worker?: string | string[];

    script?: string | string[];
    scriptAttribute?: string | string[];
    scriptElement?: string | string[];

    style?: string | string[];
    styleAttribute?: string | string[];
    styleElement?: string | string[];
  };
}

Special source values include:

• csp.self: 'self'
• csp.none: 'none'
• csp.unsafeEval: 'unsafe-eval'
• csp.wasmUnsafeEval: 'wasm-unsafe-eval'
• csp.unsafeHashes: 'unsafe-hashes'
• csp.unsafeInline: 'unsafe-inline'
• csp.strictDynamic: 'strict-dynamic'
• csp.reportSample: 'report-sample'
• csp.inlineSpeculationRules: 'inline-speculation-rules'

Cache

Cache control

Cache-Control header parser.

import { cache } from "@bit-js/web-utils";

// Parse options to header value
cache.control(options);

// No options
cache.control(); // "public,max-age=604800"

Available options are:

export interface ControlOptions {
  maxAge?: number;
  sMaxAge?: number;

  noCache?: boolean;
  noStore?: boolean;
  noTransform?: boolean;

  mustRevalidate?: boolean;
  proxyRevalidate?: boolean;

  mustUnderstand?: boolean;

  staleWhileRevalidate?: boolean;
  staleIfError?: boolean;

  private?: boolean;
  public?: boolean;
  immutable?: boolean;

  minFresh?: number;
  onlyIfCached?: boolean;
}

Server timing

Set server timing metrics.

import { serverTiming } from "@bit-js/web-utils";

// Define the metric
const startTime = serverTiming.metric("resolveTime");

// Start the timer
const result = startTime();

// Do some tasks
resolve();

// Calculate the result and modify the header pairs (string[][])
result.attach(headers);

// Or append to a Headers object
result.append(headers);

Other utilities

Escape HTML

Escape special HTML characters.

import { escapeHTML } from "@bit-js/web-utils";

escapeHTML("<p>Hello</p>");

Escape Base64URL

Convert base64 to base64url.

import { escapeBase64URL } from "@bit-js/web-utils";

escapeBase64URL("abase64string");

Render safe HTML

Render safe HTML with tagged temlate strings.

import { html } from "@bit-js/web-utils";

html`<p>${content}</p>`; // content is automatically escaped
html`<p>!${content}</p>`; // Disable escaping by prefixing !

The content can be a string, number, boolean, null, undefined or an array of those types.