feat: add getAtomsFromMF

src/component/elements/MolecularFormulaInput.jsx

@@ -1,8 +1,9 @@
 /** @jsxImportSource @emotion/react */
 import { css } from '@emotion/react';
-import { MF } from 'mf-parser';
 import { useCallback, useState } from 'react';
 
+import getAtomsFromMF from '../../data/utilities/getAtomsFromMF';
+
 const inputStyle = css`
   text-align: center;
 
@@ -38,7 +39,7 @@ function MolecularFormulaInput({ onSave, previousMF }) {
 
   const checkMF = useCallback((mf) => {
     try {
-      new MF(mf);
+      getAtomsFromMF(mf);
       return true;
     } catch (error) {
       return false;

src/data/molecules/Molecule.js

@@ -1,7 +1,7 @@
-import { MF } from 'mf-parser';
 import { Molecule as OCLMolecule } from 'openchemlib/full';
 
 import generateID from '../utilities/generateID';
+import getAtomsFromMF from '../utilities/getAtomsFromMF';
 
 /**
  * @param {object} [options={}]
@@ -19,8 +19,7 @@ export function initMolecule(options = {}) {
   molecule.mw = mfInfo.relativeWeight;
   molecule.svg = mol.toSVG(50, 50);
 
-  const mf = new MF(molecule.mf);
-  molecule.atoms = mf.getInfo().atoms;
+  molecule.atoms = getAtomsFromMF(molecule.mf);
   return molecule;
 }
 

src/data/utilities/__tests__/getAtomsFromMF.test.js

@@ -0,0 +1,13 @@
+import getAtomsFromMF from '../getAtomsFromMF';
+
+describe('getAtomsFromMF', () => {
+  it('correct mf', () => {
+    const atoms = getAtomsFromMF('C10 H20 Cl O3 Br2 C3 Cl3');
+    expect(atoms).toStrictEqual({ C: 13, H: 20, Cl: 4, O: 3, Br: 2 });
+  });
+  it('wrong mf', () => {
+    expect(() => {
+      getAtomsFromMF('ab C10 H20 Cl O3 Br2 C3 Cl3');
+    }).toThrow('MF can not be parsed: ab C10 H20 Cl O3 Br2 C3 Cl3');
+  });
+});

src/data/utilities/getAtomsFromMF.js

@@ -0,0 +1,23 @@
+const mfCheck = /^(?:[A-Z][a-z]?\d* *)+$/;
+
+export default function getAtomsFromMF(mf) {
+  if (!mfCheck.test(mf)) {
+    throw Error(`MF can not be parsed: ${mf}`);
+  }
+  const atoms = {};
+  const parts = mf.matchAll(/(?<atom>[A-Z][a-z]?)(?<number>[0-9]*)/g);
+  for (const part of parts) {
+    let { atom, number } = part.groups;
+    if (number === '') {
+      number = 1;
+    } else {
+      number = Number(number);
+    }
+    if (!atoms[atom]) {
+      atoms[atom] = 0;
+    }
+    atoms[atom] += number;
+  }
+
+  return atoms;
+}