fix: float(i) returns 0 if value is missing

valueKind has 3 values: 0 if present, 1 if not present ('.' in Cif), 2 if unknown ('?' in Cif)

src/parser/cif-parser.ts

@@ -23,6 +23,7 @@ import { Structure } from '../ngl';
 import StructureBuilder from '../structure/structure-builder';
 import { NumberArray } from '../types'
 import ChemCompMap from '../store/chemcomp-map'
+import { Column } from 'molstar/lib/mol-data/db/column'
 
 const reAtomSymbol = /^\D{1,2}/ // atom symbol in atom_site_label
 
@@ -1081,20 +1082,20 @@ class CifParser extends StructureParser {
       }
 
       if (field = cif.categories.reflns?.getField('d_resolution_high') ?? cif.categories.refine?.getField('ls_d_res_high')) {
-        if (Number.isFinite(valData = field.float(0))) {
-          s.header.resolution = valData
+        if (field.valueKind(0) === 0) { // is value present?
+          s.header.resolution = field.float(0)
         }
       }
 
       if ( field = cif.categories.refine?.getField('ls_R_factor_R_free')) {
-        if (Number.isFinite(valData = field.float(0))) {
-          s.header.rFree = valData
+        if (field.valueKind(0) === 0) { // is value present?
+          s.header.rFree = field.float(0)
         }
       }
 
       if ( field = cif.categories.refine?.getField('ls_R_factor_R_work')) {
-        if (Number.isFinite(valData = field.float(0))) {
-          s.header.rFree = valData
+        if (field.valueKind(0) === 0) { // is value present?
+          s.header.rFree = field.float(0)
         }
       }