boolean-expressions/dist/util/extractVariables.js

Boolean expression parser and evaluator. Makes use of the Ohm grammar package with grammar rules found [here](https://github.com/avadavat/boolean-expressions/blob/master/src/grammar/grammarRules.ts).

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
// Splits by parentheses, white space, and special characters.
var splitRegex = new RegExp(/[ ()|&~!^]+/g);
var reservedKeywords = new Set([
    "and",
    "not",
    "or",
    "xor",
    "if",
    "then",
    "iff",
    "only",
    "true",
    "false",
    "equals",
    "imply",
    "implies",
    "nimply",
    "nimplies",
    "xnor",
    "nand",
    "nor"
]);
/**
 * Returns a list of all the unique variable names in the given expression.
 */
function extractVariables(expression) {
    var words = expression.split(splitRegex);
    // Any word that isn't a reserved keyword is a variable.
    var variables = words
        .filter(function (word) { return word.length > 0; })
        .filter(function (word) { return /^[A-Za-z0-9]+$/.test(word); })
        .filter(function (word) { return !reservedKeywords.has(word.toLowerCase()); });
    // Only count each variable once.
    var uniqueVariables = Array.from(new Set(variables));
    return uniqueVariables;
}
exports.default = extractVariables;