transformation-matrix/build-commonjs/fromString.js

2d transformation matrix functions written in ES6 syntax. Tree shaking ready!

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.fromString = fromString;
exports.fromStringLegacy = fromStringLegacy;
/**
 * @ignore
 * @type {RegExp}
 */
const matrixRegex = /^matrix\(\s*([0-9_+-.e]+)\s*,\s*([0-9_+-.e]+)\s*,\s*([0-9_+-.e]+)\s*,\s*([0-9_+-.e]+)\s*,\s*([0-9_+-.e]+)\s*,\s*([0-9_+-.e]+)\s*\)$/i;

/**
 * Parse a string formatted as matrix(a,b,c,d,e,f)
 * @param string {string} String with an affine matrix
 * @returns {Matrix} Affine Matrix
 *
 * @example
 * > fromString('matrix(1,2,3,4,5,6)')
 * {a: 1, b: 2, c: 3, d: 4, c: 5, e: 6}
 */
function fromString(string) {
  const parseFloatOrThrow = number => {
    const n = parseFloat(number);
    if (Number.isFinite(n)) return n; // excludes NaN, +Infinite, -Infinite
    throw new Error(`'${string}' is not a matrix`);
  };
  const prefix = string.substring(0, 7).toLowerCase();
  const suffix = string.substring(string.length - 1);
  const body = string.substring(7, string.length - 1);
  const elements = body.split(',');
  if (prefix === 'matrix(' && suffix === ')' && elements.length === 6) {
    return {
      a: parseFloatOrThrow(elements[0]),
      b: parseFloatOrThrow(elements[1]),
      c: parseFloatOrThrow(elements[2]),
      d: parseFloatOrThrow(elements[3]),
      e: parseFloatOrThrow(elements[4]),
      f: parseFloatOrThrow(elements[5])
    };
  }
  throw new Error(`'${string}' is not a matrix`);
}

/**
 * Parse a string formatted as matrix(a,b,c,d,e,f) - Legacy implementation of `fromString(matrix)`;
 * Read this PR for details {@link https://github.com/chrvadala/transformation-matrix/pull/107}
 * @param string {string} String with an affine matrix
 * @deprecated
 * @returns {Matrix} Affine Matrix
 *
 * @example
 * > fromStringLegacy('matrix(1,2,3,4,5,6)')
 * {a: 1, b: 2, c: 3, d: 4, c: 5, e: 6}
 */
function fromStringLegacy(string) {
  const parsed = string.match(matrixRegex);
  if (parsed === null || parsed.length < 7) throw new Error(`'${string}' is not a matrix`);
  return {
    a: parseFloat(parsed[1]),
    b: parseFloat(parsed[2]),
    c: parseFloat(parsed[3]),
    d: parseFloat(parsed[4]),
    e: parseFloat(parsed[5]),
    f: parseFloat(parsed[6])
  };
}