diff --git a/package-lock.json b/package-lock.json
new file mode 100644
index 0000000..48fae8e
--- /dev/null
+++ b/package-lock.json
@@ -0,0 +1,98 @@
+{
+  "name": "excel2json-wasm",
+  "version": "1.0.2",
+  "lockfileVersion": 2,
+  "requires": true,
+  "packages": {
+    "": {
+      "name": "excel2json-wasm",
+      "version": "1.0.2",
+      "license": "MIT",
+      "dependencies": {
+        "fast-text-encoding": "^1.0.0"
+      },
+      "devDependencies": {
+        "rollup": "^1.1.2"
+      }
+    },
+    "node_modules/@types/estree": {
+      "version": "0.0.39",
+      "resolved": "https://registry.npmjs.org/@types/estree/-/estree-0.0.39.tgz",
+      "integrity": "sha512-EYNwp3bU+98cpU4lAWYYL7Zz+2gryWH1qbdDTidVd6hkiR6weksdbMadyXKXNPEkQFhXM+hVO9ZygomHXp+AIw==",
+      "dev": true
+    },
+    "node_modules/@types/node": {
+      "version": "11.9.3",
+      "resolved": "https://registry.npmjs.org/@types/node/-/node-11.9.3.tgz",
+      "integrity": "sha512-DMiqG51GwES/c4ScBY0u5bDlH44+oY8AeYHjY1SGCWidD7h08o1dfHue/TGK7REmif2KiJzaUskO+Q0eaeZ2fQ==",
+      "dev": true
+    },
+    "node_modules/acorn": {
+      "version": "6.4.2",
+      "resolved": "https://registry.npmjs.org/acorn/-/acorn-6.4.2.tgz",
+      "integrity": "sha512-XtGIhXwF8YM8bJhGxG5kXgjkEuNGLTkoYqVE+KMR+aspr4KGYmKYg7yUe3KghyQ9yheNwLnjmzh/7+gfDBmHCQ==",
+      "dev": true,
+      "bin": {
+        "acorn": "bin/acorn"
+      },
+      "engines": {
+        "node": ">=0.4.0"
+      }
+    },
+    "node_modules/fast-text-encoding": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/fast-text-encoding/-/fast-text-encoding-1.0.0.tgz",
+      "integrity": "sha512-R9bHCvweUxxwkDwhjav5vxpFvdPGlVngtqmx4pIZfSUhM/Q4NiIUHB456BAf+Q1Nwu3HEZYONtu+Rya+af4jiQ=="
+    },
+    "node_modules/rollup": {
+      "version": "1.1.2",
+      "resolved": "https://registry.npmjs.org/rollup/-/rollup-1.1.2.tgz",
+      "integrity": "sha512-OkdMxqMl8pWoQc5D8y1cIinYQPPLV8ZkfLgCzL6SytXeNA2P7UHynEQXI9tYxuAjAMsSyvRaWnyJDLHMxq0XAg==",
+      "dev": true,
+      "dependencies": {
+        "@types/estree": "0.0.39",
+        "@types/node": "*",
+        "acorn": "^6.0.5"
+      },
+      "bin": {
+        "rollup": "bin/rollup"
+      }
+    }
+  },
+  "dependencies": {
+    "@types/estree": {
+      "version": "0.0.39",
+      "resolved": "https://registry.npmjs.org/@types/estree/-/estree-0.0.39.tgz",
+      "integrity": "sha512-EYNwp3bU+98cpU4lAWYYL7Zz+2gryWH1qbdDTidVd6hkiR6weksdbMadyXKXNPEkQFhXM+hVO9ZygomHXp+AIw==",
+      "dev": true
+    },
+    "@types/node": {
+      "version": "11.9.3",
+      "resolved": "https://registry.npmjs.org/@types/node/-/node-11.9.3.tgz",
+      "integrity": "sha512-DMiqG51GwES/c4ScBY0u5bDlH44+oY8AeYHjY1SGCWidD7h08o1dfHue/TGK7REmif2KiJzaUskO+Q0eaeZ2fQ==",
+      "dev": true
+    },
+    "acorn": {
+      "version": "6.4.2",
+      "resolved": "https://registry.npmjs.org/acorn/-/acorn-6.4.2.tgz",
+      "integrity": "sha512-XtGIhXwF8YM8bJhGxG5kXgjkEuNGLTkoYqVE+KMR+aspr4KGYmKYg7yUe3KghyQ9yheNwLnjmzh/7+gfDBmHCQ==",
+      "dev": true
+    },
+    "fast-text-encoding": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/fast-text-encoding/-/fast-text-encoding-1.0.0.tgz",
+      "integrity": "sha512-R9bHCvweUxxwkDwhjav5vxpFvdPGlVngtqmx4pIZfSUhM/Q4NiIUHB456BAf+Q1Nwu3HEZYONtu+Rya+af4jiQ=="
+    },
+    "rollup": {
+      "version": "1.1.2",
+      "resolved": "https://registry.npmjs.org/rollup/-/rollup-1.1.2.tgz",
+      "integrity": "sha512-OkdMxqMl8pWoQc5D8y1cIinYQPPLV8ZkfLgCzL6SytXeNA2P7UHynEQXI9tYxuAjAMsSyvRaWnyJDLHMxq0XAg==",
+      "dev": true,
+      "requires": {
+        "@types/estree": "0.0.39",
+        "@types/node": "*",
+        "acorn": "^6.0.5"
+      }
+    }
+  }
+}
diff --git a/yarn.lock b/yarn.lock
index e3b3ada..65329c0 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -3,25 +3,30 @@
 
 
 "@types/estree@0.0.39":
-  version "0.0.39"
-  resolved "https://registry.yarnpkg.com/@types/estree/-/estree-0.0.39.tgz#e177e699ee1b8c22d23174caaa7422644389509f"
+  "integrity" "sha512-EYNwp3bU+98cpU4lAWYYL7Zz+2gryWH1qbdDTidVd6hkiR6weksdbMadyXKXNPEkQFhXM+hVO9ZygomHXp+AIw=="
+  "resolved" "https://registry.npmjs.org/@types/estree/-/estree-0.0.39.tgz"
+  "version" "0.0.39"
 
 "@types/node@*":
-  version "11.9.3"
-  resolved "https://registry.yarnpkg.com/@types/node/-/node-11.9.3.tgz#14adbb5ab8cd563f549fbae8dbe92e0b7d6e76cc"
+  "integrity" "sha512-DMiqG51GwES/c4ScBY0u5bDlH44+oY8AeYHjY1SGCWidD7h08o1dfHue/TGK7REmif2KiJzaUskO+Q0eaeZ2fQ=="
+  "resolved" "https://registry.npmjs.org/@types/node/-/node-11.9.3.tgz"
+  "version" "11.9.3"
 
-acorn@^6.0.5:
-  version "6.1.0"
-  resolved "https://registry.yarnpkg.com/acorn/-/acorn-6.1.0.tgz#b0a3be31752c97a0f7013c5f4903b71a05db6818"
+"acorn@^6.0.5":
+  "integrity" "sha512-XtGIhXwF8YM8bJhGxG5kXgjkEuNGLTkoYqVE+KMR+aspr4KGYmKYg7yUe3KghyQ9yheNwLnjmzh/7+gfDBmHCQ=="
+  "resolved" "https://registry.npmjs.org/acorn/-/acorn-6.4.2.tgz"
+  "version" "6.4.2"
 
-fast-text-encoding@^1.0.0:
-  version "1.0.0"
-  resolved "https://registry.yarnpkg.com/fast-text-encoding/-/fast-text-encoding-1.0.0.tgz#3e5ce8293409cfaa7177a71b9ca84e1b1e6f25ef"
+"fast-text-encoding@^1.0.0":
+  "integrity" "sha512-R9bHCvweUxxwkDwhjav5vxpFvdPGlVngtqmx4pIZfSUhM/Q4NiIUHB456BAf+Q1Nwu3HEZYONtu+Rya+af4jiQ=="
+  "resolved" "https://registry.npmjs.org/fast-text-encoding/-/fast-text-encoding-1.0.0.tgz"
+  "version" "1.0.0"
 
-rollup@^1.1.2:
-  version "1.1.2"
-  resolved "https://registry.yarnpkg.com/rollup/-/rollup-1.1.2.tgz#8d094b85683b810d0c05a16bd7618cf70d48eba7"
+"rollup@^1.1.2":
+  "integrity" "sha512-OkdMxqMl8pWoQc5D8y1cIinYQPPLV8ZkfLgCzL6SytXeNA2P7UHynEQXI9tYxuAjAMsSyvRaWnyJDLHMxq0XAg=="
+  "resolved" "https://registry.npmjs.org/rollup/-/rollup-1.1.2.tgz"
+  "version" "1.1.2"
   dependencies:
     "@types/estree" "0.0.39"
     "@types/node" "*"
-    acorn "^6.0.5"
+    "acorn" "^6.0.5"