224 lines
6.7 KiB
JavaScript
224 lines
6.7 KiB
JavaScript
'use strict';
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//
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// Allowed token characters:
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//
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// '!', '#', '$', '%', '&', ''', '*', '+', '-',
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// '.', 0-9, A-Z, '^', '_', '`', a-z, '|', '~'
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//
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// tokenChars[32] === 0 // ' '
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// tokenChars[33] === 1 // '!'
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// tokenChars[34] === 0 // '"'
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// ...
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//
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// prettier-ignore
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const tokenChars = [
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 0 - 15
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 16 - 31
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0, 1, 0, 1, 1, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, // 32 - 47
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1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, // 48 - 63
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0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 64 - 79
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1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, // 80 - 95
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1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 96 - 111
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1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0 // 112 - 127
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];
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/**
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* Adds an offer to the map of extension offers or a parameter to the map of
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* parameters.
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*
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* @param {Object} dest The map of extension offers or parameters
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* @param {String} name The extension or parameter name
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* @param {(Object|Boolean|String)} elem The extension parameters or the
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* parameter value
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* @private
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*/
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function push(dest, name, elem) {
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if (dest[name] === undefined) dest[name] = [elem];
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else dest[name].push(elem);
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}
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/**
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* Parses the `Sec-WebSocket-Extensions` header into an object.
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*
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* @param {String} header The field value of the header
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* @return {Object} The parsed object
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* @public
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*/
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function parse(header) {
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const offers = Object.create(null);
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if (header === undefined || header === '') return offers;
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let params = Object.create(null);
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let mustUnescape = false;
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let isEscaping = false;
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let inQuotes = false;
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let extensionName;
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let paramName;
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let start = -1;
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let end = -1;
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let i = 0;
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for (; i < header.length; i++) {
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const code = header.charCodeAt(i);
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if (extensionName === undefined) {
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if (end === -1 && tokenChars[code] === 1) {
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if (start === -1) start = i;
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} else if (code === 0x20 /* ' ' */ || code === 0x09 /* '\t' */) {
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if (end === -1 && start !== -1) end = i;
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} else if (code === 0x3b /* ';' */ || code === 0x2c /* ',' */) {
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if (start === -1) {
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throw new SyntaxError(`Unexpected character at index ${i}`);
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}
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if (end === -1) end = i;
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const name = header.slice(start, end);
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if (code === 0x2c) {
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push(offers, name, params);
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params = Object.create(null);
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} else {
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extensionName = name;
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}
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start = end = -1;
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} else {
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throw new SyntaxError(`Unexpected character at index ${i}`);
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}
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} else if (paramName === undefined) {
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if (end === -1 && tokenChars[code] === 1) {
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if (start === -1) start = i;
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} else if (code === 0x20 || code === 0x09) {
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if (end === -1 && start !== -1) end = i;
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} else if (code === 0x3b || code === 0x2c) {
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if (start === -1) {
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throw new SyntaxError(`Unexpected character at index ${i}`);
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}
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if (end === -1) end = i;
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push(params, header.slice(start, end), true);
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if (code === 0x2c) {
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push(offers, extensionName, params);
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params = Object.create(null);
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extensionName = undefined;
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}
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start = end = -1;
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} else if (code === 0x3d /* '=' */ && start !== -1 && end === -1) {
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paramName = header.slice(start, i);
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start = end = -1;
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} else {
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throw new SyntaxError(`Unexpected character at index ${i}`);
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}
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} else {
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//
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// The value of a quoted-string after unescaping must conform to the
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// token ABNF, so only token characters are valid.
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// Ref: https://tools.ietf.org/html/rfc6455#section-9.1
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//
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if (isEscaping) {
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if (tokenChars[code] !== 1) {
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throw new SyntaxError(`Unexpected character at index ${i}`);
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}
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if (start === -1) start = i;
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else if (!mustUnescape) mustUnescape = true;
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isEscaping = false;
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} else if (inQuotes) {
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if (tokenChars[code] === 1) {
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if (start === -1) start = i;
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} else if (code === 0x22 /* '"' */ && start !== -1) {
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inQuotes = false;
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end = i;
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} else if (code === 0x5c /* '\' */) {
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isEscaping = true;
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} else {
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throw new SyntaxError(`Unexpected character at index ${i}`);
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}
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} else if (code === 0x22 && header.charCodeAt(i - 1) === 0x3d) {
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inQuotes = true;
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} else if (end === -1 && tokenChars[code] === 1) {
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if (start === -1) start = i;
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} else if (start !== -1 && (code === 0x20 || code === 0x09)) {
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if (end === -1) end = i;
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} else if (code === 0x3b || code === 0x2c) {
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if (start === -1) {
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throw new SyntaxError(`Unexpected character at index ${i}`);
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}
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if (end === -1) end = i;
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let value = header.slice(start, end);
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if (mustUnescape) {
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value = value.replace(/\\/g, '');
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mustUnescape = false;
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}
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push(params, paramName, value);
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if (code === 0x2c) {
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push(offers, extensionName, params);
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params = Object.create(null);
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extensionName = undefined;
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}
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paramName = undefined;
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start = end = -1;
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} else {
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throw new SyntaxError(`Unexpected character at index ${i}`);
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}
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}
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}
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if (start === -1 || inQuotes) {
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throw new SyntaxError('Unexpected end of input');
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}
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if (end === -1) end = i;
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const token = header.slice(start, end);
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if (extensionName === undefined) {
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push(offers, token, params);
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} else {
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if (paramName === undefined) {
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push(params, token, true);
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} else if (mustUnescape) {
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push(params, paramName, token.replace(/\\/g, ''));
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} else {
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push(params, paramName, token);
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}
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push(offers, extensionName, params);
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}
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return offers;
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}
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/**
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* Builds the `Sec-WebSocket-Extensions` header field value.
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*
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* @param {Object} extensions The map of extensions and parameters to format
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* @return {String} A string representing the given object
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* @public
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*/
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function format(extensions) {
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return Object.keys(extensions)
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.map((extension) => {
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let configurations = extensions[extension];
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if (!Array.isArray(configurations)) configurations = [configurations];
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return configurations
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.map((params) => {
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return [extension]
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.concat(
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Object.keys(params).map((k) => {
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let values = params[k];
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if (!Array.isArray(values)) values = [values];
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return values
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.map((v) => (v === true ? k : `${k}=${v}`))
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.join('; ');
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})
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)
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.join('; ');
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})
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.join(', ');
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})
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.join(', ');
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}
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module.exports = { format, parse };
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