chore: address PR comments. make a pureCopy but test if empty recor…

…d is being miscategorized (for this purpose) as a presence

packages/ERTP/src/displayInfo.js

@@ -1,4 +1,5 @@
 import { assert, details, q } from '@agoric/assert';
+import { pureCopy, passStyleOf, REMOTE_STYLE } from '@agoric/marshal';
 
 // TODO: assertSubset and assertKeysAllowed are copied from Zoe. Move
 // this code to a location where it can be used by ERTP and Zoe
@@ -40,3 +41,12 @@ export const assertDisplayInfo = allegedDisplayInfo => {
   const displayInfoKeys = harden(['decimalPlaces']);
   assertKeysAllowed(displayInfoKeys, allegedDisplayInfo);
 };
+
+export const coerceDisplayInfo = allegedDisplayInfo => {
+  if (passStyleOf(allegedDisplayInfo) === REMOTE_STYLE) {
+    return harden({});
+  }
+  allegedDisplayInfo = pureCopy(allegedDisplayInfo);
+  assertDisplayInfo(allegedDisplayInfo);
+  return allegedDisplayInfo;
+};

packages/ERTP/src/issuer.js

@@ -10,7 +10,7 @@ import { isPromise } from '@agoric/promise-kit';
 
 import { makeAmountMath, MathKind } from './amountMath';
 import { makeInterface, ERTPKind } from './interfaces';
-import { assertDisplayInfo } from './displayInfo';
+import { coerceDisplayInfo } from './displayInfo';
 
 import './types';
 
@@ -23,7 +23,7 @@ function makeIssuerKit(
   displayInfo = undefined,
 ) {
   assert.typeof(allegedName, 'string');
-  assertDisplayInfo(displayInfo);
+  displayInfo = coerceDisplayInfo(displayInfo);
 
   const brand = Remotable(
     makeInterface(allegedName, ERTPKind.BRAND),

packages/ERTP/src/types.js

@@ -99,13 +99,14 @@
 
 /**
  * @typedef {Object} DisplayInfo
- * @property {number} decimalPlaces
+ * @property {number=} decimalPlaces
  *   Tells the display software how many decimal places to move the
  *   decimal over to the left, or in other words, which position corresponds to whole
  *   numbers. We require fungible digital assets to be represented in
  *   integers, in the smallest unit (i.e. USD might be represented in mill,
  *   a thousandth of a dollar. In that case, `decimalPlaces` would be 3.)
- *   For non-fungible digital assets, this should be left as undefined.
+ *   This property is optional, and for non-fungible digital assets,
+ *   should not be specified.
  *   The decimalPlaces property should be used for *display purposes only*. Any
  *   other use is an anti-pattern.
  */

packages/ERTP/test/unitTests/test-issuerObj.js

@@ -20,7 +20,7 @@ test('issuer.getBrand, brand.isMyIssuer', t => {
 test('brand.getDisplayInfo()', t => {
   const displayInfo = harden({ decimalPlaces: 3 });
   const { brand } = makeIssuerKit('fungible', MathKind.NAT, displayInfo);
-  t.is(brand.getDisplayInfo(), displayInfo);
+  t.deepEqual(brand.getDisplayInfo(), displayInfo);
   const display = amount => {
     const { brand: myBrand, value } = amount;
     const { decimalPlaces } = myBrand.getDisplayInfo();
@@ -37,12 +37,19 @@ test('brand.getDisplayInfo()', t => {
 
 test('bad display info', t => {
   const displayInfo = harden({ somethingUnexpected: 3 });
+  // @ts-ignore
   t.throws(() => makeIssuerKit('fungible', MathKind.NAT, displayInfo), {
     message:
       'key "somethingUnexpected" was not one of the expected keys ["decimalPlaces"]',
   });
 });
 
+test('empty display info', t => {
+  const displayInfo = harden({});
+  const { brand } = makeIssuerKit('fungible', MathKind.NAT, displayInfo);
+  t.deepEqual(brand.getDisplayInfo(), displayInfo);
+});
+
 test('amountMath from makeIssuerKit', async t => {
   const { issuer, amountMath, brand } = makeIssuerKit('fungible');
   const ibrand = await E(issuer).getBrand();