Made maxLength optional for validate.string.length()

Author: JamesMessinger

src/string.ts

@@ -52,19 +52,33 @@ Object.defineProperty(string, "length", { value: validateLength });
 
 
 function validateNonEmpty<T extends string>(value: T | undefined, fieldName = "value", defaultValue?: T): T {
-  return validateLength(value, 1, Infinity, fieldName, defaultValue);
+  return validateStringLength(value, 1, Infinity, fieldName, defaultValue);
 }
 
 
 function validateMinLength<T extends string>(
 value: T | undefined, minLength: number, fieldName = "value", defaultValue?: T): T {
-  return validateLength(value, minLength, Infinity, fieldName, defaultValue);
+  return validateStringLength(value, minLength, Infinity, fieldName, defaultValue);
 }
 
 
 function validateMaxLength<T extends string>(
 value: T | undefined, maxLength: number, fieldName = "value", defaultValue?: T): T {
-  return validateLength(value, 0, maxLength, fieldName, defaultValue);
+  return validateStringLength(value, 0, maxLength, fieldName, defaultValue);
+}
+
+
+function validateLength<T extends string>(
+value: T | undefined, minLength: number, maxLength?: number, fieldName = "value", defaultValue?: T): T {
+  if (typeof maxLength === "string") {
+    defaultValue = fieldName as T;
+    fieldName = maxLength;
+    maxLength = undefined;
+  }
+  if (maxLength === undefined) {
+    maxLength = minLength;
+  }
+  return validateStringLength(value, minLength, maxLength, fieldName, defaultValue);
 }
 
 
@@ -79,7 +93,7 @@ function validateNonWhitespace<T extends string>(value: T | undefined, fieldName
 }
 
 
-function validateLength<T extends string>(
+function validateStringLength<T extends string>(
 value: T | undefined, minLength = 1, maxLength = Infinity, fieldName = "value", defaultValue?: T): T {
   value = type.string(value, fieldName, defaultValue);
 

test/specs/string-length.spec.js

@@ -11,10 +11,20 @@ describe("validate.string.length()", () => {
     expect(validate.string.length("hello", 5, 10)).to.equal("hello");
   });
 
+  it("should validate strings that meet the exact length", () => {
+    expect(validate.string.length("a", 1)).to.equal("a");
+    expect(validate.string.length("Hello, world!", 13)).to.equal("Hello, world!");
+    expect(validate.string.length("hello", 5)).to.equal("hello");
+  });
+
   it("should validate default values", () => {
     expect(validate.string.length(undefined, 0, 1, "name", "A")).to.equal("A");
     expect(validate.string.length(undefined, 10, 50, "name", "Hello, world!")).to.equal("Hello, world!");
     expect(validate.string.length(undefined, 5, 10, "name", "hello")).to.equal("hello");
+
+    expect(validate.string.length(undefined, 1, "name", "A")).to.equal("A");
+    expect(validate.string.length(undefined, 13, "name", "Hello, world!")).to.equal("Hello, world!");
+    expect(validate.string.length(undefined, 5, "name", "hello")).to.equal("hello");
   });
 
   it("should throw an error for strings that don't meet the minimum and maximum", () => {
@@ -29,6 +39,18 @@ describe("validate.string.length()", () => {
     expect(tooLong("Hello, world!", 1, 10)).to.throw(RangeError, 'Invalid value: "Hello, world!". It cannot be more than 10 characters.');
   });
 
+  it("should throw an error for strings that don't meet the exact length", () => {
+    function tooLong (value, length) {
+      return () => {
+        validate.string.length(value, length);
+      };
+    }
+
+    expect(tooLong(" ", 0)).to.throw(RangeError, 'Invalid value: " ". It must be exactly 0 characters.');
+    expect(tooLong("abc", 1)).to.throw(RangeError, 'Invalid value: "abc". It must be exactly 1 character.');
+    expect(tooLong("Hello, world!", 10)).to.throw(RangeError, 'Invalid value: "Hello, world!". It must be exactly 10 characters.');
+  });
+
   it("should throw an error for defaults that don't meet the maximum", () => {
     function invalidDefault (defaultValue, min, max) {
       return () => {
@@ -41,4 +63,16 @@ describe("validate.string.length()", () => {
     expect(invalidDefault("Hello, world!", 1, 10)).to.throw(RangeError, 'Invalid name: "Hello, world!". It cannot be more than 10 characters.');
   });
 
+  it("should throw an error for defaults that don't meet the exact length", () => {
+    function invalidDefault (defaultValue, length) {
+      return () => {
+        validate.string.length(undefined, length, "name", defaultValue);
+      };
+    }
+
+    expect(invalidDefault(" ", 0)).to.throw(RangeError, 'Invalid name: " ". It must be exactly 0 characters.');
+    expect(invalidDefault("abc", 1)).to.throw(RangeError, 'Invalid name: "abc". It must be exactly 1 character.');
+    expect(invalidDefault("Hello, world!", 10)).to.throw(RangeError, 'Invalid name: "Hello, world!". It must be exactly 10 characters.');
+  });
+
 });