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- const COMMA = ',';
- const COLON = ':';
- const LEFT_SQUARE_BRACKET = '[';
- const RIGHT_SQUARE_BRACKET = ']';
- const LEFT_CURLY_BRACKET = '{';
- const RIGHT_CURLY_BRACKET = '}';
- // Recursively encodes the supplied object according to the canonical JSON form
- // as specified at http://wiki.laptop.org/go/Canonical_JSON. It's a restricted
- // dialect of JSON in which keys are lexically sorted, floats are not allowed,
- // and only double quotes and backslashes are escaped.
- function canonicalize(object) {
- const buffer = [];
- if (typeof object === 'string') {
- buffer.push(canonicalizeString(object));
- } else if (typeof object === 'boolean') {
- buffer.push(JSON.stringify(object));
- } else if (Number.isInteger(object)) {
- buffer.push(JSON.stringify(object));
- } else if (object === null) {
- buffer.push(JSON.stringify(object));
- } else if (Array.isArray(object)) {
- buffer.push(LEFT_SQUARE_BRACKET);
- let first = true;
- object.forEach((element) => {
- if (!first) {
- buffer.push(COMMA);
- }
- first = false;
- buffer.push(canonicalize(element));
- });
- buffer.push(RIGHT_SQUARE_BRACKET);
- } else if (typeof object === 'object') {
- buffer.push(LEFT_CURLY_BRACKET);
- let first = true;
- Object.keys(object)
- .sort()
- .forEach((property) => {
- if (!first) {
- buffer.push(COMMA);
- }
- first = false;
- buffer.push(canonicalizeString(property));
- buffer.push(COLON);
- buffer.push(canonicalize(object[property]));
- });
- buffer.push(RIGHT_CURLY_BRACKET);
- } else {
- throw new TypeError('cannot encode ' + object.toString());
- }
- return buffer.join('');
- }
- // String canonicalization consists of escaping backslash (\) and double
- // quote (") characters and wrapping the resulting string in double quotes.
- function canonicalizeString(string) {
- const escapedString = string.replace(/\\/g, '\\\\').replace(/"/g, '\\"');
- return '"' + escapedString + '"';
- }
- module.exports = {
- canonicalize,
- };
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