vendor/GLTFExporter.js
function isNormalizedNormalAttribute(normal) {
      if (cachedData.attributes.has(normal)) {
        return false;
      }

      var v = new THREE.Vector3();

      for (var i = 0, il = normal.count; i < il; i++) {
        // 0.0005 is from glTF-validator
        if (Math.abs(v.fromArray(normal.array, i * 3).length() - 1.0) > 0.0005)
          return false;
      }

      return true;
    }
function isNormalizedNormalAttribute(normal) {
      if (cachedData.attributes.has(normal)) {
        return false;
      }

      var v = new THREE.Vector3();

      for (var i = 0, il = normal.count; i < il; i++) {
        // 0.0005 is from glTF-validator
        if (Math.abs(v.fromArray(normal.array, i * 3).length() - 1.0) > 0.0005)
          return false;
      }

      return true;
    }
function isNormalizedNormalAttribute ( normal ) { if ( cachedData . attributes . has ( normal ) ) { return false ; } var v = new THREE . Vector3 ( ) ; for ( var i = 0 , il = normal . count ; i < il ; i ++ ) { // 0.0005 is from glTF-validator if ( Math . abs ( v . fromArray ( normal . array , i * 3 ) . length ( ) - 1.0 ) > 0.0005 ) return false ; } return true ; }
Checks if normal attribute values are normalized.

@param {THREE.BufferAttribute} normal
@returns {Boolean}
Checks if normal attribute values are normalized .