fix number precision

packages/base-formula/src/eval.ts

@@ -1,4 +1,5 @@
 import { makeErrorCell, isErrorCell } from "./error";
+import { valueToString } from "./number";
 import { MAX_EVAL_DEPTH } from "./types";
 import type { FormulaAST, OpCode } from "./ast";
 import type { Value, EvalContext } from "./types";
@@ -102,7 +103,7 @@ function evalOp(
 
   switch (op as Exclude<OpCode, "neg" | "not">) {
     case "+":
-      if (typeof a === "string" || typeof b === "string") return (a == null ? "" : String(a)) + (b == null ? "" : String(b));
+      if (typeof a === "string" || typeof b === "string") return valueToString(a) + valueToString(b);
       if (a == null || b == null) return null;
       return Number(a) + Number(b);
     case "-": return a == null || b == null ? null : Number(a) - Number(b);

packages/base-formula/src/functions/coercion.ts

@@ -1,4 +1,5 @@
 import { register } from "./registry";
+import { valueToString } from "../number";
 
 register({
   name: "toNumber", arity: { min: 1, max: 1 }, paramTypes: "any", returnType: "number",
@@ -11,6 +12,6 @@ register({
 });
 register({
   name: "toString", arity: { min: 1, max: 1 }, paramTypes: "any", returnType: "string",
-  eval: ([v]) => v == null ? "" : String(v),
+  eval: ([v]) => valueToString(v),
   doc: "Converts the value to a string.", category: "coercion",
 });

packages/base-formula/src/functions/string.ts

@@ -1,6 +1,7 @@
 import { register } from "./registry";
+import { valueToString } from "../number";
 
-const s = (v: unknown): string => v == null ? "" : String(v);
+const s = (v: unknown): string => valueToString(v);
 
 register({
   name: "concat", arity: { min: 1, max: null }, paramTypes: "variadic-any", returnType: "string",

packages/base-formula/src/index.client.ts

@@ -11,3 +11,4 @@ export * from "./format";
 export { registry, register } from "./functions/registry";
 export type { FormulaFn } from "./functions/registry";
 export * from "./graph";
+export * from "./number";

packages/base-formula/src/index.server.ts

@@ -12,3 +12,4 @@ export { registry, register } from "./functions/index";
 export type { FormulaFn } from "./functions/index";
 export * from "./graph";
 export * from "./eval";
+export * from "./number";

packages/base-formula/src/number.ts

@@ -0,0 +1,10 @@
+export function snapNumber(n: number): number {
+  if (!Number.isFinite(n)) return n;
+  return Number(n.toPrecision(15));
+}
+
+export function valueToString(v: unknown): string {
+  if (v == null) return "";
+  if (typeof v === "number") return String(snapNumber(v));
+  return String(v);
+}