diff --git a/README.md b/README.md
index f2b2830..a687e60 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-# TSDX Bootstrap
+# File Commons
 
 Useful methods for file-related functions.
 
diff --git a/package.json b/package.json
index e122a1a..b189bf3 100644
--- a/package.json
+++ b/package.json
@@ -1,5 +1,5 @@
 {
-  "version": "0.1.0",
+  "version": "1.0.1",
   "license": "MIT",
   "main": "dist/index.js",
   "typings": "dist/index.d.ts",
@@ -26,8 +26,12 @@
       "pre-commit": "tsdx lint"
     }
   },
-  "name": "file-commons",
-  "author": "Allan Crisostomo",
+  "name": "@theoryofnekomata/file-commons",
+  "author": "TheoryOfNekomata <allan.crisostomo@outlook.com>",
+  "repository": {
+    "type": "git",
+    "url":"https://code.modal.sh/TheoryOfNekomata/file-commons.git"
+  },
   "module": "dist/file-commons.esm.js",
   "devDependencies": {
     "@types/crypto-js": "^3.1.47",
diff --git a/src/calculateHash.test.ts b/src/calculateHash.test.ts
new file mode 100644
index 0000000..1b05336
--- /dev/null
+++ b/src/calculateHash.test.ts
@@ -0,0 +1,25 @@
+import * as fc from 'fast-check'
+import calculateHash from './calculateHash'
+
+it('should exist', () => {
+  expect(calculateHash).toBeDefined()
+})
+
+it('should be a callable', () => {
+  expect(typeof calculateHash).toBe('function')
+})
+
+it('should accept a minimum of 1 argument', () => {
+  expect(calculateHash).toHaveLength(1)
+})
+
+it('should return a string', () => {
+  fc.assert(
+    fc.property(
+      fc.string(),
+      s => {
+        expect(typeof calculateHash(s)).toBe('string')
+      }
+    )
+  )
+})
diff --git a/src/dataUriToBlob.test.ts b/src/dataUriToBlob.test.ts
new file mode 100644
index 0000000..b17e518
--- /dev/null
+++ b/src/dataUriToBlob.test.ts
@@ -0,0 +1,25 @@
+import * as fc from 'fast-check'
+import dataUriToBlob from './dataUriToBlob'
+
+it('should exist', () => {
+  expect(dataUriToBlob).toBeDefined()
+})
+
+it('should be a callable', () => {
+  expect(typeof dataUriToBlob).toBe('function')
+})
+
+it('should accept 2 arguments', () => {
+  expect(dataUriToBlob).toHaveLength(2)
+})
+
+it('should throw an error for invalid parameters', () => {
+  fc.assert(
+    fc.property(
+      fc.anything().filter(s => typeof s !== 'string'),
+      s => {
+        expect(() => dataUriToBlob(s as string)).toThrow(TypeError)
+      }
+    )
+  )
+})
diff --git a/src/dataUriToBlob.ts b/src/dataUriToBlob.ts
index 83bcab7..868ef86 100644
--- a/src/dataUriToBlob.ts
+++ b/src/dataUriToBlob.ts
@@ -1,11 +1,19 @@
 type DataUriToBlob = (dataUri: string, name?: string) => Blob
 
+const DATA_URI_PREFIX = 'data:'
+const DATA_TYPE_DELIMITER = ';'
+const DATA_START = ','
+
 const dataUriToBlob: DataUriToBlob = (dataUri, name) => {
+  if (typeof dataUri as unknown !== 'string') {
+    throw TypeError('Argument should be a string.')
+  }
+
   const [encoding, base64] = dataUri
-    .slice('data:'.length)
-    .split(',')
+    .slice(DATA_URI_PREFIX.length)
+    .split(DATA_START)
   const binary = atob(base64)
-  const [type,] = encoding.split(';')
+  const [type,] = encoding.split(DATA_TYPE_DELIMITER)
   const ab = new ArrayBuffer(binary.length)
   const ia = new Uint8Array(ab)
   for (let i = 0; i < binary.length; i++) {
@@ -18,3 +26,5 @@ const dataUriToBlob: DataUriToBlob = (dataUri, name) => {
 }
 
 export default dataUriToBlob
+
+// TODO make code portable to Node! Maybe return a buffer instead of blob?
diff --git a/src/formatFileSize.test.ts b/src/formatFileSize.test.ts
index c9b8219..bb73e76 100644
--- a/src/formatFileSize.test.ts
+++ b/src/formatFileSize.test.ts
@@ -47,7 +47,7 @@ describe('on non-numeric arguments', () => {
       fc.property(
         fc.anything().filter(v => typeof v !== 'number'),
         v => {
-          expect(() => formatFileSize(v)).toThrow(TypeError)
+          expect(() => formatFileSize(v as number)).toThrow(TypeError)
         }
       )
     )
diff --git a/src/formatFileSize.ts b/src/formatFileSize.ts
index 7a3c91d..3a7c1a5 100644
--- a/src/formatFileSize.ts
+++ b/src/formatFileSize.ts
@@ -1,13 +1,12 @@
 import numeral from 'numeral'
 
-type FormatFileSize = (maybeNumber: unknown) => string
+type FormatFileSize = (n: number) => string
 
-const formatFileSize: FormatFileSize = maybeNumber => {
-  if (typeof maybeNumber! !== 'number') {
+const formatFileSize: FormatFileSize = n => {
+  if (typeof n as unknown !== 'number') {
     throw TypeError('Argument should be a number.')
   }
 
-  const n = maybeNumber as number
   if (isNaN(n)) {
     throw RangeError('Cannot format NaN.')
   }
diff --git a/src/formatRawFileSize.test.ts b/src/formatRawFileSize.test.ts
index 5c2ac95..303edbf 100644
--- a/src/formatRawFileSize.test.ts
+++ b/src/formatRawFileSize.test.ts
@@ -18,7 +18,7 @@ it('should throw an error on non-numeric arguments', () => {
     fc.property(
       fc.anything().filter(v => typeof v !== 'number'),
       v => {
-        expect(() => formatRawFileSize(v)).toThrow(TypeError)
+        expect(() => formatRawFileSize(v as number)).toThrow(TypeError)
       }
     )
   )
diff --git a/src/formatRawFileSize.ts b/src/formatRawFileSize.ts
index 05bf44f..4ab00c8 100644
--- a/src/formatRawFileSize.ts
+++ b/src/formatRawFileSize.ts
@@ -1,14 +1,12 @@
 import numeral from 'numeral'
 
-type FormatRawFileSize = (maybeNumber: unknown) => string
+type FormatRawFileSize = (n: number) => string
 
-const formatRawFileSize: FormatRawFileSize = maybeNumber => {
-    if (typeof maybeNumber! !== 'number') {
+const formatRawFileSize: FormatRawFileSize = n => {
+    if (typeof n as unknown !== 'number') {
         throw TypeError('Argument should be a number.')
     }
 
-    const n = maybeNumber as number
-
     if (isNaN(n)) {
         throw RangeError('Cannot format NaN.')
     }
diff --git a/src/index.ts b/src/index.ts
index 7ca45ba..0dac6d4 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -2,10 +2,14 @@ import calculateHash from './calculateHash'
 import dataUriToBlob from './dataUriToBlob'
 import formatFileSize from './formatFileSize'
 import formatRawFileSize from './formatRawFileSize'
+import isValidFilename from './isValidFileName'
+import isValidMimeType from './isValidMimeType'
 
 export {
   calculateHash,
   dataUriToBlob,
   formatFileSize,
   formatRawFileSize,
+  isValidFilename,
+  isValidMimeType,
 }
diff --git a/src/isValidFileName.test.ts b/src/isValidFileName.test.ts
new file mode 100644
index 0000000..c07013c
--- /dev/null
+++ b/src/isValidFileName.test.ts
@@ -0,0 +1,119 @@
+import * as fc from 'fast-check'
+import isValidFilename, { IsValidFilenameConfig } from './isValidFileName'
+
+it('should exist', () => {
+  expect(isValidFilename).toBeDefined()
+})
+
+it('should be a callable', () => {
+  expect(typeof isValidFilename).toBe('function')
+})
+
+it('should accept a minimum of 1 argument', () => {
+  expect(isValidFilename).toHaveLength(1)
+})
+
+it('should throw an error given invalid param shapes', () => {
+  fc.assert(
+    fc.property(
+      fc.object().filter(o => !('validExtensions' in o)),
+      params => {
+        expect(() => isValidFilename(params as unknown as IsValidFilenameConfig)).toThrow(TypeError)
+      }
+    )
+  )
+})
+
+describe('on valid extensions', () => {
+  it('should throw an error given non-string and non-array values', () => {
+    fc.assert(
+      fc.property(
+        fc.record({
+          validExtensions: fc.anything().filter(e => !(typeof e === 'string' || Array.isArray(e)))
+        }),
+        params => {
+          expect(() => isValidFilename(params as unknown as IsValidFilenameConfig)).toThrow(TypeError)
+        }
+      )
+    )
+  })
+  it('should throw an error given empty arrays', () => {
+    expect(() => isValidFilename({ validExtensions: [] })).toThrow(RangeError)
+  })
+  it('should throw an error given non-string arrays', () => {
+    fc.assert(
+      fc.property(
+        fc.record({
+          validExtensions: fc.array(fc.anything().filter(e => typeof e !== 'string'), 1, 20),
+        }),
+        params => {
+          expect(() => isValidFilename(params as unknown as IsValidFilenameConfig)).toThrow(TypeError)
+        }
+      )
+    )
+  })
+  it('should return a main callable given strings', () => {
+    fc.assert(
+      fc.property(
+        fc.record<IsValidFilenameConfig>({
+          validExtensions: fc.string(),
+        }),
+        params => {
+          expect(typeof isValidFilename(params)).toBe('function')
+        }
+      )
+    )
+  })
+  it('should return a main callable given string arrays', () => {
+    fc.assert(
+      fc.property(
+        fc.record<IsValidFilenameConfig>({
+          validExtensions: fc.array(fc.string(), 1, 20),
+        }),
+        params => {
+          expect(typeof isValidFilename(params)).toBe('function')
+        }
+      )
+    )
+  })
+})
+
+describe('on main callable', () => {
+  it('should throw an error for non-string params', () => {
+    fc.assert(
+      fc.property(
+        fc.tuple(
+          fc.record<IsValidFilenameConfig>({
+            validExtensions: fc.oneof(
+              fc.string(),
+              fc.array(fc.string(), 1, 20),
+            ),
+          }),
+          fc.anything().filter(v => typeof v !== 'string'),
+        ),
+        ([params, maybeFileName]) => {
+          expect(() => isValidFilename(params)(maybeFileName as string)).toThrow(TypeError)
+        }
+      )
+    )
+  })
+
+  it('should return a boolean for string params', () => {
+    fc.assert(
+      fc.property(
+        fc.tuple(
+          fc.record<IsValidFilenameConfig>({
+            validExtensions: fc.oneof(
+              fc.string(),
+              fc.array(fc.string(), 1, 20),
+            ),
+          }),
+          fc.string(),
+        ),
+        ([params, maybeFileName]) => {
+          expect(typeof isValidFilename(params)(maybeFileName)).toBe('boolean')
+        }
+      )
+    )
+  })
+})
diff --git a/src/isValidFileName.ts b/src/isValidFileName.ts
new file mode 100644
index 0000000..a8352b1
--- /dev/null
+++ b/src/isValidFileName.ts
@@ -0,0 +1,65 @@
+const EXTENSION_DELIMITER = '.'
+const MULTIPLE_VALID_EXTENSION_DELIMITER = ' '
+
+export type IsValidFilenameConfig = {
+  validExtensions: string | string[]
+  allowMultipleExtensions?: boolean
+}
+
+type IsValidFileName = (config: IsValidFilenameConfig) => (maybeFileName: string) => boolean
+
+const isValidFileName: IsValidFileName = config => {
+  let validExtensionsArray: string[]
+  const maybeValidExtensions = config.validExtensions as unknown
+  if (typeof maybeValidExtensions === 'string') {
+    validExtensionsArray = (config.validExtensions as string)
+      .split(MULTIPLE_VALID_EXTENSION_DELIMITER)
+      .filter(p => p.trim().length > 0)
+  } else if (
+    Array.isArray(maybeValidExtensions)
+    && (config.validExtensions as unknown[]).every(s => typeof s === 'string')
+  ) {
+    if ((config.validExtensions as unknown[]).length < 1) {
+      throw RangeError('There must be at least 1 valid extension defined.')
+    }
+    validExtensionsArray = config.validExtensions as string[]
+  } else {
+    throw TypeError('Valid extensions should be a space-delimited string or a string array.')
+  }
+
+  // strip . in valid extensions for easier matching
+  const validExtensions = validExtensionsArray.map(e => (
+    e.startsWith(EXTENSION_DELIMITER)
+      ? e.slice(EXTENSION_DELIMITER.length)
+      : e
+  ))
+
+  return maybeFileName => {
+    if (typeof maybeFileName as unknown !== 'string') {
+      throw TypeError('Argument should be a string.')
+    }
+
+    const fileName = maybeFileName as string
+    const [, ...extensions] = fileName.split(EXTENSION_DELIMITER)
+
+    if (config.allowMultipleExtensions) {
+      return validExtensions.reduce<boolean>(
+        (isValid, validExtension) => (
+          isValid
+          || extensions.includes(validExtension)
+        ),
+        false
+      )
+    }
+
+    return validExtensions.reduce<boolean>(
+      (isValid, validExtension) => (
+        isValid
+        || extensions.join(EXTENSION_DELIMITER).endsWith(validExtension)
+      ),
+      false
+    )
+  }
+}
+
+export default isValidFileName
diff --git a/src/isValidMimeType.test.ts b/src/isValidMimeType.test.ts
new file mode 100644
index 0000000..46902ce
--- /dev/null
+++ b/src/isValidMimeType.test.ts
@@ -0,0 +1,119 @@
+import * as fc from 'fast-check'
+import isValidMimeType, { IsValidMimeTypeConfig } from './isValidMimeType'
+
+it('should exist', () => {
+  expect(isValidMimeType).toBeDefined()
+})
+
+it('should be a callable', () => {
+  expect(typeof isValidMimeType).toBe('function')
+})
+
+it('should accept a minimum of 1 argument', () => {
+  expect(isValidMimeType).toHaveLength(1)
+})
+
+it('should throw an error given invalid param shapes', () => {
+  fc.assert(
+    fc.property(
+      fc.object().filter(o => !('validMimeTypes' in o)),
+      params => {
+        expect(() => isValidMimeType(params as unknown as IsValidMimeTypeConfig)).toThrow(TypeError)
+      }
+    )
+  )
+})
+
+describe('on valid MIME types', () => {
+  it('should throw an error given non-string and non-array values', () => {
+    fc.assert(
+      fc.property(
+        fc.record({
+          validMimeTypes: fc.anything().filter(e => !(typeof e === 'string' || Array.isArray(e)))
+        }),
+        params => {
+          expect(() => isValidMimeType(params as unknown as IsValidMimeTypeConfig)).toThrow(TypeError)
+        }
+      )
+    )
+  })
+  it('should throw an error given empty arrays', () => {
+    expect(() => isValidMimeType({ validMimeTypes: [] })).toThrow(RangeError)
+  })
+  it('should throw an error given non-string arrays', () => {
+    fc.assert(
+      fc.property(
+        fc.record({
+          validMimeTypes: fc.array(fc.anything().filter(e => typeof e !== 'string'), 1, 20),
+        }),
+        params => {
+          expect(() => isValidMimeType(params as unknown as IsValidMimeTypeConfig)).toThrow(TypeError)
+        }
+      )
+    )
+  })
+  it('should return a main callable given strings', () => {
+    fc.assert(
+      fc.property(
+        fc.record<IsValidMimeTypeConfig>({
+          validMimeTypes: fc.string(),
+        }),
+        params => {
+          expect(typeof isValidMimeType(params)).toBe('function')
+        }
+      )
+    )
+  })
+  it('should return a main callable given string arrays', () => {
+    fc.assert(
+      fc.property(
+        fc.record<IsValidMimeTypeConfig>({
+          validMimeTypes: fc.array(fc.string(), 1, 20),
+        }),
+        params => {
+          expect(typeof isValidMimeType(params)).toBe('function')
+        }
+      )
+    )
+  })
+})
+
+describe('on main callable', () => {
+  it('should throw an error for non-string params', () => {
+    fc.assert(
+      fc.property(
+        fc.tuple(
+          fc.record<IsValidMimeTypeConfig>({
+            validMimeTypes: fc.oneof(
+              fc.string(),
+              fc.array(fc.string(), 1, 20),
+            ),
+          }),
+          fc.anything().filter(v => typeof v !== 'string'),
+        ),
+        ([params, maybeFileName]) => {
+          expect(() => isValidMimeType(params)(maybeFileName as string)).toThrow(TypeError)
+        }
+      )
+    )
+  })
+
+  it('should return a boolean for string params', () => {
+    fc.assert(
+      fc.property(
+        fc.tuple(
+          fc.record<IsValidMimeTypeConfig>({
+            validMimeTypes: fc.oneof(
+              fc.string(),
+              fc.array(fc.string(), 1, 20),
+            ),
+          }),
+          fc.string(),
+        ),
+        ([params, maybeFileName]) => {
+          expect(typeof isValidMimeType(params)(maybeFileName)).toBe('boolean')
+        }
+      )
+    )
+  })
+})
diff --git a/src/isValidMimeType.ts b/src/isValidMimeType.ts
new file mode 100644
index 0000000..3fe1b8e
--- /dev/null
+++ b/src/isValidMimeType.ts
@@ -0,0 +1,61 @@
+const MULTIPLE_VALID_MIME_TYPE_DELIMITER = ' '
+const CATCH_ALL_MIME_TYPES = ['*', '*/*']
+const MIME_TYPE_FORMAT_DELIMITER = '/'
+
+// catch-all for format, e.g. "image/*" matches all MIME types starting with "image/"
+const MIME_TYPE_FORMAT_CATCH_ALL = '*'
+
+export type IsValidMimeTypeConfig = {
+  validMimeTypes: string | string[]
+}
+
+type IsValidMimeType = (config: IsValidMimeTypeConfig) => (mimeType: string) => boolean
+
+const isValidMimeType: IsValidMimeType = config => {
+  let validMimeTypes: string[]
+  const maybeValidMimeTypes = config.validMimeTypes as unknown
+  if (typeof maybeValidMimeTypes === 'string') {
+    validMimeTypes = (config.validMimeTypes as string)
+      .split(MULTIPLE_VALID_MIME_TYPE_DELIMITER)
+      .filter(p => p.trim().length > 0)
+  } else if (
+    Array.isArray(maybeValidMimeTypes)
+    && (config.validMimeTypes as unknown[]).every(s => typeof s === 'string')
+  ) {
+    if ((config.validMimeTypes as unknown[]).length < 1) {
+      throw RangeError('There must be at least 1 valid extension defined.')
+    }
+    validMimeTypes = config.validMimeTypes as string[]
+  } else {
+    throw TypeError('Valid MimeTypes should be a space-delimited string or a string array.')
+  }
+
+  return mimeType => {
+    if (typeof mimeType as unknown !== 'string') {
+      throw TypeError('Argument should be a string.')
+    }
+
+    // short-circuit valid MIME types that are catch-all
+    if (validMimeTypes.some(a => CATCH_ALL_MIME_TYPES.includes(a))) {
+      return true
+    }
+
+    return (
+      validMimeTypes.reduce<boolean>(
+        (isValid, validMimeType) => {
+          const [type, format] = validMimeType.split(MIME_TYPE_FORMAT_DELIMITER)
+
+          // maybe short circuit matching format catch-all valid MIME types?
+          if (format === MIME_TYPE_FORMAT_CATCH_ALL) {
+            return isValid || mimeType.startsWith(type + MIME_TYPE_FORMAT_DELIMITER)
+          }
+
+          return isValid || mimeType === validMimeType
+        },
+        false,
+      )
+    )
+  }
+}
+
+export default isValidMimeType