Add fromSeconds

packages/tendermint-rpc/src/dates.spec.ts

@@ -4,6 +4,7 @@ import {
   DateTime,
   DateWithNanoseconds,
   fromRfc3339WithNanoseconds,
+  fromSeconds,
   toRfc3339WithNanoseconds,
   toSeconds,
 } from "./dates";
@@ -61,6 +62,62 @@ describe("dates", () => {
     });
   });
 
+  describe("fromSeconds", () => {
+    it("works", () => {
+      {
+        const date = fromSeconds(1608029846);
+        expect(date).toEqual(fromRfc3339WithNanoseconds("2020-12-15T10:57:26Z"));
+      }
+      {
+        const date = fromSeconds(1608029846, 0);
+        expect(date).toEqual(fromRfc3339WithNanoseconds("2020-12-15T10:57:26Z"));
+      }
+      {
+        const date = fromSeconds(1608029846, 1);
+        expect(date).toEqual(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.000000001Z"));
+      }
+      {
+        const date = fromSeconds(1608029846, 10);
+        expect(date).toEqual(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.000000010Z"));
+      }
+      {
+        const date = fromSeconds(1608029846, 100);
+        expect(date).toEqual(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.000000100Z"));
+      }
+      {
+        const date = fromSeconds(1608029846, 1000);
+        expect(date).toEqual(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.000001000Z"));
+      }
+      {
+        const date = fromSeconds(1608029846, 10000);
+        expect(date).toEqual(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.000010000Z"));
+      }
+      {
+        const date = fromSeconds(1608029846, 100000);
+        expect(date).toEqual(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.000100000Z"));
+      }
+      {
+        const date = fromSeconds(1608029846, 1000000);
+        expect(date).toEqual(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.001000000Z"));
+      }
+      {
+        const date = fromSeconds(1608029846, 10000000);
+        expect(date).toEqual(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.010000000Z"));
+      }
+      {
+        const date = fromSeconds(1608029846, 100000000);
+        expect(date).toEqual(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.100000000Z"));
+      }
+    });
+
+    it("throws for nanos out of range", () => {
+      expect(() => fromSeconds(1608029846, 1000000000)).toThrow();
+      expect(() => fromSeconds(1608029846, -1)).toThrow();
+      expect(() => fromSeconds(1608029846, 1.2)).toThrow();
+      expect(() => fromSeconds(1608029846, NaN)).toThrow();
+    });
+  });
+
   describe("toSeconds", () => {
     it("works", () => {
       {

packages/tendermint-rpc/src/dates.ts

@@ -1,4 +1,5 @@
 import { fromRfc3339 } from "@cosmjs/encoding";
+import { Uint32 } from "@cosmjs/math";
 import { ReadonlyDate } from "readonly-date";
 
 export interface ReadonlyDateWithNanoseconds extends ReadonlyDate {
@@ -25,6 +26,16 @@ export function toRfc3339WithNanoseconds(dateTime: ReadonlyDateWithNanoseconds):
   return `${millisecondIso.slice(0, -1)}${nanoseconds.padStart(6, "0")}Z`;
 }
 
+export function fromSeconds(seconds: number, nanos = 0): DateWithNanoseconds {
+  const checkedNanos = new Uint32(nanos).toNumber();
+  if (checkedNanos > 999_999_999) {
+    throw new Error("Nano seconds must not exceed 999999999");
+  }
+  const out: DateWithNanoseconds = new Date(seconds * 1000 + Math.floor(checkedNanos / 1000000));
+  out.nanoseconds = checkedNanos % 1000000;
+  return out;
+}
+
 /**
  * Caclulates the UNIX timestamp in seconds as well as the nanoseconds after the given second.
  *

packages/tendermint-rpc/src/index.ts

@@ -5,6 +5,7 @@ export {
   DateTime,
   ReadonlyDateWithNanoseconds,
   fromRfc3339WithNanoseconds,
+  fromSeconds,
   toRfc3339WithNanoseconds,
   toSeconds,
 } from "./dates";