Replace proj/Units enum with typedef

src/ol/proj/Projection.js

@@ -6,13 +6,13 @@ import {METERS_PER_UNIT} from './Units.js';
 /**
  * @typedef {Object} Options
  * @property {string} code The SRS identifier code, e.g. `EPSG:4326`.
- * @property {import("./Units.js").default|string} [units] Units. Required unless a
+ * @property {import("./Units.js").Units} [units] Units. Required unless a
  * proj4 projection is defined for `code`.
  * @property {import("../extent.js").Extent} [extent] The validity extent for the SRS.
  * @property {string} [axisOrientation='enu'] The axis orientation as specified in Proj4.
  * @property {boolean} [global=false] Whether the projection is valid for the whole globe.
  * @property {number} [metersPerUnit] The meters per unit for the SRS.
- * If not provided, the `units` are used to get the meters per unit from the {@link module:ol/proj/Units~METERS_PER_UNIT}
+ * If not provided, the `units` are used to get the meters per unit from the {@link METERS_PER_UNIT}
  * lookup table.
  * @property {import("../extent.js").Extent} [worldExtent] The world extent for the SRS.
  * @property {function(number, import("../coordinate.js").Coordinate):number} [getPointResolution]
@@ -65,9 +65,9 @@ class Projection {
      * `this.extent_` and `this.worldExtent_` must be configured properly for each
      * tile.
      * @private
-     * @type {import("./Units.js").default}
+     * @type {import("./Units.js").Units}
      */
-    this.units_ = /** @type {import("./Units.js").default} */ (options.units);
+    this.units_ = /** @type {import("./Units.js").Units} */ (options.units);
 
     /**
      * Validity extent of the projection in projected coordinates. For projections
@@ -153,7 +153,7 @@ class Projection {
 
   /**
    * Get the units of this projection.
-   * @return {import("./Units.js").default} Units.
+   * @return {import("./Units.js").Units} Units.
    * @api
    */
   getUnits() {

src/ol/proj/Units.js

@@ -3,58 +3,20 @@
  */
 
 /**
- * Projection units: `'degrees'`, `'ft'`, `'m'`, `'pixels'`, `'tile-pixels'` or
- * `'us-ft'`.
- * @enum {string}
+ * @typedef {'radians' | 'degrees' | 'ft' | 'm' | 'pixels' | 'tile-pixels' | 'us-ft'} Units
+ * Projection units.
  */
-const Units = {
-  /**
-   * Radians
-   * @api
-   */
-  RADIANS: 'radians',
-  /**
-   * Degrees
-   * @api
-   */
-  DEGREES: 'degrees',
-  /**
-   * Feet
-   * @api
-   */
-  FEET: 'ft',
-  /**
-   * Meters
-   * @api
-   */
-  METERS: 'm',
-  /**
-   * Pixels
-   * @api
-   */
-  PIXELS: 'pixels',
-  /**
-   * Tile Pixels
-   * @api
-   */
-  TILE_PIXELS: 'tile-pixels',
-  /**
-   * US Feet
-   * @api
-   */
-  USFEET: 'us-ft',
-};
 
 /**
  * See http://duff.ess.washington.edu/data/raster/drg/docs/geotiff.txt
  * @type {Object<number, Units>}
  */
 const unitByCode = {
-  '9001': Units.METERS,
-  '9002': Units.FEET,
-  '9003': Units.USFEET,
-  '9101': Units.RADIANS,
-  '9102': Units.DEGREES,
+  '9001': 'm',
+  '9002': 'ft',
+  '9003': 'us-ft',
+  '9101': 'radians',
+  '9102': 'degrees',
 };
 
 /**
@@ -65,18 +27,26 @@ export function fromCode(code) {
   return unitByCode[code];
 }
 
+/**
+ * @typedef {Object} MetersPerUnitLookup
+ * @property {number} radians Radians
+ * @property {number} degrees Degrees
+ * @property {number} ft  Feet
+ * @property {number} m Meters
+ * @property {number} us-ft US feet
+ */
+
 /**
  * Meters per unit lookup table.
  * @const
- * @type {Object<Units, number>}
+ * @type {MetersPerUnitLookup}
  * @api
  */
-export const METERS_PER_UNIT = {};
-// use the radius of the Normal sphere
-METERS_PER_UNIT[Units.RADIANS] = 6370997 / (2 * Math.PI);
-METERS_PER_UNIT[Units.DEGREES] = (2 * Math.PI * 6370997) / 360;
-METERS_PER_UNIT[Units.FEET] = 0.3048;
-METERS_PER_UNIT[Units.METERS] = 1;
-METERS_PER_UNIT[Units.USFEET] = 1200 / 3937;
-
-export default Units;
+export const METERS_PER_UNIT = {
+  // use the radius of the Normal sphere
+  'radians': 6370997 / (2 * Math.PI),
+  'degrees': (2 * Math.PI * 6370997) / 360,
+  'ft': 0.3048,
+  'm': 1,
+  'us-ft': 1200 / 3937,
+};

src/ol/proj/epsg3857.js

@@ -2,7 +2,6 @@
  * @module ol/proj/epsg3857
  */
 import Projection from './Projection.js';
-import Units from './Units.js';
 
 /**
  * Radius of WGS84 sphere
@@ -48,7 +47,7 @@ class EPSG3857Projection extends Projection {
   constructor(code) {
     super({
       code: code,
-      units: Units.METERS,
+      units: 'm',
       extent: EXTENT,
       global: true,
       worldExtent: WORLD_EXTENT,

src/ol/proj/epsg4326.js

@@ -2,7 +2,6 @@
  * @module ol/proj/epsg4326
  */
 import Projection from './Projection.js';
-import Units from './Units.js';
 
 /**
  * Semi-major radius of the WGS84 ellipsoid.
@@ -42,7 +41,7 @@ class EPSG4326Projection extends Projection {
   constructor(code, opt_axisOrientation) {
     super({
       code: code,
-      units: Units.DEGREES,
+      units: 'degrees',
       extent: EXTENT,
       axisOrientation: opt_axisOrientation,
       global: true,

src/ol/proj/proj4.js

@@ -2,7 +2,6 @@
  * @module ol/proj/proj4
  */
 import Projection from './Projection.js';
-import Units from './Units.js';
 import {
   addCoordinateTransforms,
   addEquivalentProjections,
@@ -33,7 +32,7 @@ export function register(proj4) {
       const def = proj4.defs(code);
       let units = def.units;
       if (!units && def.projName === 'longlat') {
-        units = Units.DEGREES;
+        units = 'degrees';
       }
       addProjection(
         new Projection({