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- 'use strict';
- const configurationError = require('./configurationError');
- const isSingleLineString = require('./isSingleLineString');
- const isWhitespace = require('./isWhitespace');
- /**
- * @typedef {(message: string) => string} MessageFunction
- */
- /**
- * @typedef {Object} Messages
- * @property {MessageFunction} [expectedBefore]
- * @property {MessageFunction} [rejectedBefore]
- * @property {MessageFunction} [expectedAfter]
- * @property {MessageFunction} [rejectedAfter]
- * @property {MessageFunction} [expectedBeforeSingleLine]
- * @property {MessageFunction} [rejectedBeforeSingleLine]
- * @property {MessageFunction} [expectedBeforeMultiLine]
- * @property {MessageFunction} [rejectedBeforeMultiLine]
- * @property {MessageFunction} [expectedAfterSingleLine]
- * @property {MessageFunction} [rejectedAfterSingleLine]
- * @property {MessageFunction} [expectedAfterMultiLine]
- * @property {MessageFunction} [rejectedAfterMultiLine]
- */
- /**
- * @typedef {Object} WhitespaceCheckerArgs
- * @property {string} source - The source string
- * @property {number} index - The index of the character to check before
- * @property {(message: string) => void} err - If a problem is found, this callback
- * will be invoked with the relevant warning message.
- * Typically this callback will report() the problem.
- * @property {string} [errTarget] - If a problem is found, this string
- * will be sent to the relevant warning message.
- * @property {string} [lineCheckStr] - Single- and multi-line checkers
- * will use this string to determine whether they should proceed,
- * i.e. if this string is one line only, single-line checkers will check,
- * multi-line checkers will ignore.
- * If none is passed, they will use `source`.
- * @property {boolean} [onlyOneChar=false] - Only check *one* character before.
- * By default, "always-*" checks will look for the `targetWhitespace` one
- * before and then ensure there is no whitespace two before. This option
- * bypasses that second check.
- * @property {boolean} [allowIndentation=false] - Allow arbitrary indentation
- * between the `targetWhitespace` (almost definitely a newline) and the `index`.
- * With this option, the checker will see if a newline *begins* the whitespace before
- * the `index`.
- */
- /**
- * @typedef {(args: WhitespaceCheckerArgs) => void} WhitespaceChecker
- */
- /**
- * @typedef {{
- * before: WhitespaceChecker,
- * beforeAllowingIndentation: WhitespaceChecker,
- * after: WhitespaceChecker,
- * afterOneOnly: WhitespaceChecker,
- * }} WhitespaceCheckers
- */
- /**
- * Create a whitespaceChecker, which exposes the following functions:
- * - `before()`
- * - `beforeAllowingIndentation()`
- * - `after()`
- * - `afterOneOnly()`
- *
- * @param {"space" | "newline"} targetWhitespace - This is a keyword instead
- * of the actual character (e.g. " ") in order to accommodate
- * different styles of newline ("\n" vs "\r\n")
- * @param {"always" | "never" | "always-single-line" | "always-multi-line" | "never-single-line" | "never-multi-line"} expectation
- * @param {Messages} messages - An object of message functions;
- * calling `before*()` or `after*()` and the `expectation` that is passed
- * determines which message functions are required
- *
- * @returns {WhitespaceCheckers} The checker, with its exposed checking functions
- */
- module.exports = function whitespaceChecker(targetWhitespace, expectation, messages) {
- // Keep track of active arguments in order to avoid passing
- // too much stuff around, making signatures long and confusing.
- // This variable gets reset anytime a checking function is called.
- /** @type {WhitespaceCheckerArgs} */
- let activeArgs;
- /**
- * Check for whitespace *before* a character.
- * @type {WhitespaceChecker}
- */
- function before({
- source,
- index,
- err,
- errTarget,
- lineCheckStr,
- onlyOneChar = false,
- allowIndentation = false,
- }) {
- activeArgs = {
- source,
- index,
- err,
- errTarget,
- onlyOneChar,
- allowIndentation,
- };
- switch (expectation) {
- case 'always':
- expectBefore();
- break;
- case 'never':
- rejectBefore();
- break;
- case 'always-single-line':
- if (!isSingleLineString(lineCheckStr || source)) {
- return;
- }
- expectBefore(messages.expectedBeforeSingleLine);
- break;
- case 'never-single-line':
- if (!isSingleLineString(lineCheckStr || source)) {
- return;
- }
- rejectBefore(messages.rejectedBeforeSingleLine);
- break;
- case 'always-multi-line':
- if (isSingleLineString(lineCheckStr || source)) {
- return;
- }
- expectBefore(messages.expectedBeforeMultiLine);
- break;
- case 'never-multi-line':
- if (isSingleLineString(lineCheckStr || source)) {
- return;
- }
- rejectBefore(messages.rejectedBeforeMultiLine);
- break;
- default:
- throw configurationError(`Unknown expectation "${expectation}"`);
- }
- }
- /**
- * Check for whitespace *after* a character.
- * @type {WhitespaceChecker}
- */
- function after({ source, index, err, errTarget, lineCheckStr, onlyOneChar = false }) {
- activeArgs = { source, index, err, errTarget, onlyOneChar };
- switch (expectation) {
- case 'always':
- expectAfter();
- break;
- case 'never':
- rejectAfter();
- break;
- case 'always-single-line':
- if (!isSingleLineString(lineCheckStr || source)) {
- return;
- }
- expectAfter(messages.expectedAfterSingleLine);
- break;
- case 'never-single-line':
- if (!isSingleLineString(lineCheckStr || source)) {
- return;
- }
- rejectAfter(messages.rejectedAfterSingleLine);
- break;
- case 'always-multi-line':
- if (isSingleLineString(lineCheckStr || source)) {
- return;
- }
- expectAfter(messages.expectedAfterMultiLine);
- break;
- case 'never-multi-line':
- if (isSingleLineString(lineCheckStr || source)) {
- return;
- }
- rejectAfter(messages.rejectedAfterMultiLine);
- break;
- default:
- throw configurationError(`Unknown expectation "${expectation}"`);
- }
- }
- /**
- * @type {WhitespaceChecker}
- */
- function beforeAllowingIndentation(obj) {
- before({ ...obj, allowIndentation: true });
- }
- function expectBefore(messageFunc = messages.expectedBefore) {
- if (activeArgs.allowIndentation) {
- expectBeforeAllowingIndentation(messageFunc);
- return;
- }
- const _activeArgs = activeArgs;
- const source = _activeArgs.source;
- const index = _activeArgs.index;
- const oneCharBefore = source[index - 1];
- const twoCharsBefore = source[index - 2];
- if (!isValue(oneCharBefore)) {
- return;
- }
- if (
- targetWhitespace === 'space' &&
- oneCharBefore === ' ' &&
- (activeArgs.onlyOneChar || !isWhitespace(twoCharsBefore))
- ) {
- return;
- }
- assertFunction(messageFunc);
- activeArgs.err(messageFunc(activeArgs.errTarget || source[index]));
- }
- function expectBeforeAllowingIndentation(messageFunc = messages.expectedBefore) {
- const _activeArgs2 = activeArgs;
- const source = _activeArgs2.source;
- const index = _activeArgs2.index;
- const err = _activeArgs2.err;
- const expectedChar = (function () {
- if (targetWhitespace === 'newline') {
- return '\n';
- }
- })();
- let i = index - 1;
- while (source[i] !== expectedChar) {
- if (source[i] === '\t' || source[i] === ' ') {
- i--;
- continue;
- }
- assertFunction(messageFunc);
- err(messageFunc(activeArgs.errTarget || source[index]));
- return;
- }
- }
- function rejectBefore(messageFunc = messages.rejectedBefore) {
- const _activeArgs3 = activeArgs;
- const source = _activeArgs3.source;
- const index = _activeArgs3.index;
- const oneCharBefore = source[index - 1];
- if (isValue(oneCharBefore) && isWhitespace(oneCharBefore)) {
- assertFunction(messageFunc);
- activeArgs.err(messageFunc(activeArgs.errTarget || source[index]));
- }
- }
- /**
- * @type {WhitespaceChecker}
- */
- function afterOneOnly(obj) {
- after({ ...obj, onlyOneChar: true });
- }
- function expectAfter(messageFunc = messages.expectedAfter) {
- const _activeArgs4 = activeArgs;
- const source = _activeArgs4.source;
- const index = _activeArgs4.index;
- const oneCharAfter = source[index + 1];
- const twoCharsAfter = source[index + 2];
- if (!isValue(oneCharAfter)) {
- return;
- }
- if (targetWhitespace === 'newline') {
- // If index is followed by a Windows CR-LF ...
- if (
- oneCharAfter === '\r' &&
- twoCharsAfter === '\n' &&
- (activeArgs.onlyOneChar || !isWhitespace(source[index + 3]))
- ) {
- return;
- }
- // If index is followed by a Unix LF ...
- if (oneCharAfter === '\n' && (activeArgs.onlyOneChar || !isWhitespace(twoCharsAfter))) {
- return;
- }
- }
- if (
- targetWhitespace === 'space' &&
- oneCharAfter === ' ' &&
- (activeArgs.onlyOneChar || !isWhitespace(twoCharsAfter))
- ) {
- return;
- }
- assertFunction(messageFunc);
- activeArgs.err(messageFunc(activeArgs.errTarget || source[index]));
- }
- function rejectAfter(messageFunc = messages.rejectedAfter) {
- const _activeArgs5 = activeArgs;
- const source = _activeArgs5.source;
- const index = _activeArgs5.index;
- const oneCharAfter = source[index + 1];
- if (isValue(oneCharAfter) && isWhitespace(oneCharAfter)) {
- assertFunction(messageFunc);
- activeArgs.err(messageFunc(activeArgs.errTarget || source[index]));
- }
- }
- return {
- before,
- beforeAllowingIndentation,
- after,
- afterOneOnly,
- };
- };
- /**
- * @param {unknown} x
- */
- function isValue(x) {
- return x !== undefined && x !== null;
- }
- /**
- * @param {unknown} x
- * @returns {asserts x is Function}
- */
- function assertFunction(x) {
- if (typeof x !== 'function') {
- throw new TypeError(`\`${x}\` must be a function`);
- }
- }
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