Add specific error when a e-notation number gets passed

bpierre · May 15, 2023 · 680f4ad · 680f4ad
1 parent 6bbbad6
commit 680f4ad
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Showing 2 changed files with 14 additions and 0 deletions.
diff --git a/src/dnum.ts b/src/dnum.ts
@@ -36,6 +36,13 @@ export function from(
 
   value = String(value);
 
+  if (value.includes("e")) {
+    throw new Error(
+      `The passed number lost its precision: ${value}. `
+        + `Please use a string, BigInt or Dnum value instead.`,
+    );
+  }
+
   if (!value.match(NUM_RE)) {
     throw new Error(`Incorrect number: ${value}`);
   }

diff --git a/test/all.test.ts b/test/all.test.ts
@@ -624,6 +624,13 @@ describe("from()", () => {
   it("works with numbers", () => {
     expect(from(12345.29387, 18)).toEqual([12345293870000000000000n, 18]);
     expect(from(-12345.29387, 18)).toEqual([-12345293870000000000000n, 18]);
+    expect(from(10 ** 20, 0)).toEqual([100000000000000000000n, 0]);
+  });
+  it("fails when the passed number lost its precision", () => {
+    expect(() => from(10 ** 21, 0))
+      .toThrowErrorMatchingInlineSnapshot(
+        '"The passed number lost its precision: 1e+21. Please use a string, BigInt or Dnum value instead."',
+      );
   });
   it("works with bigints", () => {
     expect(from(1234529387n, 18)).toEqual([1234529387000000000000000000n, 18]);