chore: use a better API for stringifyRatio functions (#2795)

packages/ui-components/src/display/index.js

@@ -1,3 +1,4 @@
 export * from './display';
+export * from './natValue/stringifyRatioAsFraction';
 export * from './natValue/stringifyRatio';
-export * from './natValue/stringifyRatioNumerator';
+export * from './natValue/stringifyRatioAsPercent';

packages/ui-components/src/display/natValue/stringifyRatio.js

@@ -1,53 +1,48 @@
-// @ts-check
-
-import { assert } from '@agoric/assert';
-import { isNatValue } from '@agoric/ertp';
-
-// eslint-disable-next-line import/no-extraneous-dependencies
-import '@agoric/zoe/exported';
-
-import { stringifyNat } from './stringifyNat';
+import { assert, details } from '@agoric/assert';
+import { captureNum } from './helpers/captureNum';
+import { roundToDecimalPlaces } from './helpers/roundToDecimalPlaces';
 
 const PLACES_TO_SHOW = 2;
 
 /**
- * 
- * @param {Ratio} ratio 
- * @param {{ numDecimalPlaces?: number,
-    numPlacesToShow?: number,
-    denomDecimalPlaces?: number,
-    denomPlacesToShow?: number,
-    getDecimalPlaces?: Function }} [options] 
+ *
+ * @param {Ratio} ratio
+ * @param {(brand: Brand) => number | undefined} getDecimalPlaces
+ * @param {number} [placesToShow]
  * @returns {string}
  */
-export const stringifyRatio = (ratio, options) => {
-  const {
-    numPlacesToShow = PLACES_TO_SHOW,
-    denomPlacesToShow = PLACES_TO_SHOW,
-    getDecimalPlaces = undefined,
-  } = options || {};
-  let { numDecimalPlaces, denomDecimalPlaces } = options || {};
-
-  assert(isNatValue(ratio.numerator.value));
-  assert(isNatValue(ratio.denominator.value));
-
-  if (getDecimalPlaces !== undefined) {
-    numDecimalPlaces = getDecimalPlaces(ratio.numerator.brand);
-    denomDecimalPlaces = getDecimalPlaces(ratio.denominator.brand);
+export const stringifyRatio = (
+  ratio,
+  getDecimalPlaces,
+  placesToShow = PLACES_TO_SHOW,
+) => {
+  if (ratio === null || ratio === undefined) {
+    return '0';
   }
+  assert(
+    ratio && ratio.numerator,
+    details`Ratio ${ratio} did not look like a ratio`,
+  );
 
-  assert(numDecimalPlaces !== undefined, `numDecimalPlaces required`);
-  assert(denomDecimalPlaces !== undefined, `denomDecimalPlaces required`);
+  const numDecimalPlaces = getDecimalPlaces(ratio.numerator.brand);
+  const denomDecimalPlaces = getDecimalPlaces(ratio.denominator.brand);
 
-  const numeratorString = stringifyNat(
-    ratio.numerator.value,
+  assert(
     numDecimalPlaces,
-    numPlacesToShow,
+    `decimalPlaces for numerator ${ratio.numerator} must be provided`,
   );
-  const denominatorString = stringifyNat(
-    ratio.denominator.value,
+  assert(
     denomDecimalPlaces,
-    denomPlacesToShow,
+    `decimalPlaces for denominator ${ratio.denominator} must be provided`,
   );
-  return `${numeratorString} / ${denominatorString}`;
+  const denomPower = 10n ** BigInt(denomDecimalPlaces);
+  const numPower = 10n ** BigInt(numDecimalPlaces);
+  const numerator = ratio.numerator.value * denomPower;
+  const denominator = ratio.denominator.value * numPower;
+  const str = `${Number(numerator) / Number(denominator)}`;
+  const capturedNum = captureNum(str);
+  return `${capturedNum.left}.${roundToDecimalPlaces(
+    capturedNum.right,
+    placesToShow,
+  )}`;
 };

packages/ui-components/src/display/natValue/stringifyRatioAsFraction.js

@@ -0,0 +1,53 @@
+// @ts-check
+
+import { assert } from '@agoric/assert';
+import { isNatValue } from '@agoric/ertp';
+
+// eslint-disable-next-line import/no-extraneous-dependencies
+import '@agoric/zoe/exported';
+
+import { stringifyNat } from './stringifyNat';
+
+const PLACES_TO_SHOW = 2;
+
+/**
+ * @param {Ratio} ratio
+ * @param {(brand: Brand) => number | undefined } getDecimalPlaces
+ * @param {number} [numPlacesToShow]
+ * @param {number} [denomPlacesToShow]
+ * @returns {string}
+ */
+export const stringifyRatioAsFraction = (
+  ratio,
+  getDecimalPlaces,
+  numPlacesToShow = PLACES_TO_SHOW,
+  denomPlacesToShow = PLACES_TO_SHOW,
+) => {
+  assert(isNatValue(ratio.numerator.value));
+  assert(isNatValue(ratio.denominator.value));
+
+  const numDecimalPlaces = getDecimalPlaces(ratio.numerator.brand);
+  const denomDecimalPlaces = getDecimalPlaces(ratio.denominator.brand);
+
+  assert(
+    numDecimalPlaces,
+    `decimalPlaces for numerator ${ratio.numerator} must be provided`,
+  );
+  assert(
+    denomDecimalPlaces,
+    `decimalPlaces for denominator ${ratio.denominator} must be provided`,
+  );
+  const numeratorString = stringifyNat(
+    // @ts-ignore value is BigInt
+    ratio.numerator.value,
+    numDecimalPlaces,
+    numPlacesToShow,
+  );
+  const denominatorString = stringifyNat(
+    // @ts-ignore value is BigInt
+    ratio.denominator.value,
+    denomDecimalPlaces,
+    denomPlacesToShow,
+  );
+  return `${numeratorString} / ${denominatorString}`;
+};

packages/ui-components/src/display/natValue/stringifyRatioAsPercent.js

@@ -0,0 +1,54 @@
+// @ts-check
+
+import { assert, details } from '@agoric/assert';
+import '@agoric/zoe/exported';
+
+import { captureNum } from './helpers/captureNum';
+import { roundToDecimalPlaces } from './helpers/roundToDecimalPlaces';
+
+const PERCENT_BASE = 100n;
+const PLACES_TO_SHOW = 2;
+
+/**
+ * @param {Ratio} ratio
+ * @param {(brand: Brand) => number | undefined } getDecimalPlaces
+ * @param {number} [placesToShow]
+ * @returns {string}
+ */
+export const stringifyRatioAsPercent = (
+  ratio,
+  getDecimalPlaces,
+  placesToShow = PLACES_TO_SHOW,
+) => {
+  if (ratio === null || ratio === undefined) {
+    return '0';
+  }
+  assert(
+    ratio && ratio.numerator,
+    details`Ratio ${ratio} did not look like a ratio`,
+  );
+
+  const numDecimalPlaces = getDecimalPlaces(ratio.numerator.brand);
+  const denomDecimalPlaces = getDecimalPlaces(ratio.denominator.brand);
+
+  assert(
+    numDecimalPlaces,
+    `decimalPlaces for numerator ${ratio.numerator} must be provided`,
+  );
+  assert(
+    denomDecimalPlaces,
+    `decimalPlaces for denominator ${ratio.denominator} must be provided`,
+  );
+  const denomPower = 10n ** BigInt(denomDecimalPlaces);
+  const numPower = 10n ** BigInt(numDecimalPlaces);
+  // @ts-ignore value is BigInt
+  const numerator = ratio.numerator.value * denomPower * PERCENT_BASE;
+  // @ts-ignore value is BigInt
+  const denominator = ratio.denominator.value * numPower;
+  const str = `${Number(numerator) / Number(denominator)}`;
+  const capturedNum = captureNum(str);
+  return `${capturedNum.left}.${roundToDecimalPlaces(
+    capturedNum.right,
+    placesToShow,
+  )}`;
+};

packages/ui-components/test/display/natValue/test-stringifyRatio.js

@@ -6,8 +6,9 @@ import { makeRatio } from '@agoric/zoe/src/contractSupport';
 import { makeIssuerKit, MathKind } from '@agoric/ertp';
 
 import { assert, details as X } from '@agoric/assert';
+import { stringifyRatioAsFraction } from '../../../src/display/natValue/stringifyRatioAsFraction';
 import { stringifyRatio } from '../../../src/display/natValue/stringifyRatio';
-import { stringifyRatioNumerator } from '../../../src/display/natValue/stringifyRatioNumerator';
+import { stringifyRatioAsPercent } from '../../../src/display/natValue/stringifyRatioAsPercent';
 
 test('stringifyRatio dollars for one eth', t => {
   // 1 dollar is 100 cents, or 2 decimal points to the right
@@ -35,25 +36,70 @@ test('stringifyRatio dollars for one eth', t => {
     ),
   );
 
-  const options = {
-    numDecimalPlaces: 2,
-    denomDecimalPlaces: 18,
-    denomPlacesToShow: 0,
+  const getDecimalPlaces = brand => {
+    if (ethKit.brand === brand) {
+      return 18;
+    }
+    if (dollarKit.brand === brand) {
+      return 2;
+    }
+    assert.fail(X`brand ${brand} was not recognized`);
   };
 
-  t.is(stringifyRatio(ethPrice, options), '1587.24 / 1');
-  t.is(stringifyRatioNumerator(ethPrice, options), '1587.24');
+  t.is(
+    stringifyRatioAsFraction(ethPrice, getDecimalPlaces, undefined, 0),
+    '1587.24 / 1',
+  );
+
+  t.is(stringifyRatioAsFraction(ethPrice, getDecimalPlaces), '1587.24 / 1.00');
+  t.is(stringifyRatio(ethPrice, getDecimalPlaces), '1587.24');
+});
+
+test('stringifyApproxRatio - marketPrice for ETH in RUN', t => {
+  // RUN has 6 decimalPlaces
+  // 1 eth is 10^18 wei, or 18 decimal points to the right
+
+  // $1,587.24 for 1 ETH
+
+  //   denominator: {brand: Alleged: ETH brand, value: 1000000000000000000n}
+  // numerator: {brand: Alleged: Scones brand, value: 1909113516n}
+
+  const RUNKit = makeIssuerKit(
+    'RUN',
+    MathKind.NAT,
+    harden({ decimalPlaces: 6 }),
+  );
+
+  const ethKit = makeIssuerKit(
+    'ETH',
+    MathKind.NAT,
+    harden({ decimalPlaces: 18 }),
+  );
+
+  const ethPrice = harden(
+    makeRatio(
+      1909113516n, // value of 1 eth in smallest RUN denomination
+      RUNKit.brand,
+      10n ** 18n,
+      ethKit.brand,
+    ),
+  );
 
   const getDecimalPlaces = brand => {
     if (ethKit.brand === brand) {
       return 18;
     }
-    if (dollarKit.brand === brand) {
-      return 2;
+    if (RUNKit.brand === brand) {
+      return 6;
     }
     assert.fail(X`brand ${brand} was not recognized`);
   };
 
-  t.is(stringifyRatio(ethPrice, { getDecimalPlaces }), '1587.24 / 1.00');
-  t.is(stringifyRatioNumerator(ethPrice, { getDecimalPlaces }), '1587.24');
+  t.is(stringifyRatio(ethPrice, getDecimalPlaces), '1909.11');
+
+  t.is(stringifyRatio(ethPrice, getDecimalPlaces, 4), '1909.1135');
+
+  t.is(stringifyRatioAsPercent(ethPrice, getDecimalPlaces), '190911.35');
+
+  t.is(stringifyRatioAsPercent(ethPrice, getDecimalPlaces, 1), '190911.3');
 });