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/**
* @fileoverview Define the cursor which iterates tokens only in reverse.
* @author Toru Nagashima
*/
"use strict";
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
const Cursor = require("./cursor");
const utils = require("./utils");
//------------------------------------------------------------------------------
// Exports
//------------------------------------------------------------------------------
/**
* The cursor which iterates tokens only in reverse.
*/
module.exports = class BackwardTokenCursor extends Cursor {
/**
* Initializes this cursor.
* @param {Token[]} tokens The array of tokens.
* @param {Comment[]} comments The array of comments.
* @param {Object} indexMap The map from locations to indices in `tokens`.
* @param {number} startLoc The start location of the iteration range.
* @param {number} endLoc The end location of the iteration range.
*/
constructor(tokens, comments, indexMap, startLoc, endLoc) {
super();
this.tokens = tokens;
this.index = utils.getLastIndex(tokens, indexMap, endLoc);
this.indexEnd = utils.getFirstIndex(tokens, indexMap, startLoc);
}
/** @inheritdoc */
moveNext() {
if (this.index >= this.indexEnd) {
this.current = this.tokens[this.index];
this.index -= 1;
return true;
}
return false;
}
/*
*
* Shorthand for performance.
*
*/
/** @inheritdoc */
getOneToken() {
return (this.index >= this.indexEnd) ? this.tokens[this.index] : null;
}
};
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