fix: clarify invalid footprint function errors

src/footprinter.ts

@@ -364,9 +364,7 @@ export const footprinter = (): Footprinter & {
 
           if (!FOOTPRINT_FN[target.fn]) {
             throw new Error(
-              `Invalid footprint function, got "${target.fn}"${
-                target.string ? `, from string "${target.string}"` : ""
-              }`,
+              `Function not found for footprinter "${target.fn}". Specify a valid function like .dip, .lr, .p etc.`,
             )
           }
 
@@ -380,9 +378,7 @@ export const footprinter = (): Footprinter & {
         if (prop === "json") {
           if (!FOOTPRINT_FN[target.fn]) {
             throw new Error(
-              `Invalid footprint function, got "${target.fn}"${
-                target.string ? `, from string "${target.string}"` : ""
-              }`,
+              `Function not found for footprinter "${target.fn}". Specify a valid function like .dip, .lr, .p etc.`,
             )
           }
           return () => FOOTPRINT_FN[target.fn](target).parameters

tests/fp-string-error.test.ts

@@ -3,6 +3,6 @@ import { fp } from "src/footprinter"
 
 test("fp.string error", () => {
   expect(() => fp.string("nonexistentfn4_p3").circuitJson()).toThrow(
-    'Invalid footprint function, got "nonexistentfn", from string "nonexistentfn4_p3"',
+    'Function not found for footprinter "nonexistentfn". Specify a valid function like .dip, .lr, .p etc.',
   )
 })

tests/string-parser.test.ts

@@ -4,3 +4,9 @@ import { fp } from "../src/footprinter"
 test("string builder ignores empty segments", () => {
   expect(() => fp.string("0603__").circuitJson()).not.toThrow()
 })
+
+test("invalid footprint function error identifies the missing function", () => {
+  expect(() => fp.string("invalid").circuitJson()).toThrow(
+    'Function not found for footprinter "invalid". Specify a valid function like .dip, .lr, .p etc.',
+  )
+})

tests/vssop.test.ts

@@ -123,7 +123,9 @@ test("invalid_vssop6", () => {
   } catch (error) {
     const e = error as Error
     expect(e).toBeInstanceOf(Error)
-    expect(e.message).toContain("Invalid footprint function")
+    expect(e.message).toContain(
+      'Function not found for footprinter "invalid"',
+    )
   }
 })