utils.js
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/**
* @fileoverview Define utility functions for token store.
* @author Toru Nagashima
*/
"use strict";
//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------
/**
* Gets `token.range[0]` from the given token.
* @param {Node|Token|Comment} token The token to get.
* @returns {number} The start location.
* @private
*/
function getStartLocation(token) {
return token.range[0];
}
//------------------------------------------------------------------------------
// Exports
//------------------------------------------------------------------------------
/**
* Finds the index of the first token which is after the given location.
* If it was not found, this returns `tokens.length`.
* @param {(Token|Comment)[]} tokens It searches the token in this list.
* @param {number} location The location to search.
* @returns {number} The found index or `tokens.length`.
*/
exports.search = function search(tokens, location) {
const index = tokens.findIndex(el => location <= getStartLocation(el));
return index === -1 ? tokens.length : index;
};
/**
* Gets the index of the `startLoc` in `tokens`.
* `startLoc` can be the value of `node.range[1]`, so this checks about `startLoc - 1` as well.
* @param {(Token|Comment)[]} tokens The tokens to find an index.
* @param {Object} indexMap The map from locations to indices.
* @param {number} startLoc The location to get an index.
* @returns {number} The index.
*/
exports.getFirstIndex = function getFirstIndex(tokens, indexMap, startLoc) {
if (startLoc in indexMap) {
return indexMap[startLoc];
}
if ((startLoc - 1) in indexMap) {
const index = indexMap[startLoc - 1];
const token = (index >= 0 && index < tokens.length) ? tokens[index] : null;
/*
* For the map of "comment's location -> token's index", it points the next token of a comment.
* In that case, +1 is unnecessary.
*/
if (token && token.range[0] >= startLoc) {
return index;
}
return index + 1;
}
return 0;
};
/**
* Gets the index of the `endLoc` in `tokens`.
* The information of end locations are recorded at `endLoc - 1` in `indexMap`, so this checks about `endLoc - 1` as well.
* @param {(Token|Comment)[]} tokens The tokens to find an index.
* @param {Object} indexMap The map from locations to indices.
* @param {number} endLoc The location to get an index.
* @returns {number} The index.
*/
exports.getLastIndex = function getLastIndex(tokens, indexMap, endLoc) {
if (endLoc in indexMap) {
return indexMap[endLoc] - 1;
}
if ((endLoc - 1) in indexMap) {
const index = indexMap[endLoc - 1];
const token = (index >= 0 && index < tokens.length) ? tokens[index] : null;
/*
* For the map of "comment's location -> token's index", it points the next token of a comment.
* In that case, -1 is necessary.
*/
if (token && token.range[1] > endLoc) {
return index - 1;
}
return index;
}
return tokens.length - 1;
};