formipay/node_modules/@tannin/evaluate/dist/evaluate.js

var evaluate = (function () {
	'use strict';

	/**
	 * Operator callback functions.
	 *
	 * @type {Object}
	 */
	var OPERATORS = {
		'!': function( a ) {
			return ! a;
		},
		'*': function( a, b ) {
			return a * b;
		},
		'/': function( a, b ) {
			return a / b;
		},
		'%': function( a, b ) {
			return a % b;
		},
		'+': function( a, b ) {
			return a + b;
		},
		'-': function( a, b ) {
			return a - b;
		},
		'<': function( a, b ) {
			return a < b;
		},
		'<=': function( a, b ) {
			return a <= b;
		},
		'>': function( a, b ) {
			return a > b;
		},
		'>=': function( a, b ) {
			return a >= b;
		},
		'==': function( a, b ) {
			return a === b;
		},
		'!=': function( a, b ) {
			return a !== b;
		},
		'&&': function( a, b ) {
			return a && b;
		},
		'||': function( a, b ) {
			return a || b;
		},
		'?:': function( a, b, c ) {
			if ( a ) {
				throw b;
			}

			return c;
		},
	};

	/**
	 * Given an array of postfix terms and operand variables, returns the result of
	 * the postfix evaluation.
	 *
	 * @example
	 *
	 * ```js
	 * import evaluate from '@tannin/evaluate';
	 *
	 * // 3 + 4 * 5 / 6 ⇒ '3 4 5 * 6 / +'
	 * const terms = [ '3', '4', '5', '*', '6', '/', '+' ];
	 *
	 * evaluate( terms, {} );
	 * // ⇒ 6.333333333333334
	 * ```
	 *
	 * @param {string[]} postfix   Postfix terms.
	 * @param {Object}   variables Operand variables.
	 *
	 * @return {*} Result of evaluation.
	 */
	function evaluate( postfix, variables ) {
		var stack = [],
			i, j, args, getOperatorResult, term, value;

		for ( i = 0; i < postfix.length; i++ ) {
			term = postfix[ i ];

			getOperatorResult = OPERATORS[ term ];
			if ( getOperatorResult ) {
				// Pop from stack by number of function arguments.
				j = getOperatorResult.length;
				args = Array( j );
				while ( j-- ) {
					args[ j ] = stack.pop();
				}

				try {
					value = getOperatorResult.apply( null, args );
				} catch ( earlyReturn ) {
					return earlyReturn;
				}
			} else if ( variables.hasOwnProperty( term ) ) {
				value = variables[ term ];
			} else {
				value = +term;
			}

			stack.push( value );
		}

		return stack[ 0 ];
	}

	return evaluate;

}());