<NME> tools.js
<BEF> ADDFILE
<MSG> feat: make cropper image clearly

<DFF> @@ -0,0 +1,64 @@
+/**
+ * String type check
+ */
+exports.isStr = (v) => typeof v === 'string';
+/**
+ * Number type check
+ */
+exports.isNum = (v) => typeof v === 'number';
+/**
+ * Array type check
+ */
+exports.isArr = Array.isArray;
+/**
+ * undefined type check
+ */
+exports.isUndef = (v) => v === undefined;
+
+exports.isTrue = (v) => v === true;
+
+exports.isFalse = (v) => v === false;
+/**
+ * Function type check
+ */
+exports.isFunc = (v) => typeof v === 'function';
+/**
+ * Quick object check - this is primarily used to tell
+ * Objects from primitive values when we know the value
+ * is a JSON-compliant type.
+ */
+exports.isObj = exports.isObject = (obj) => {
+  return obj !== null && typeof obj === 'object'
+}
+
+/**
+ * Strict object type check. Only returns true
+ * for plain JavaScript objects.
+ */
+const _toString = Object.prototype.toString;
+exports.isPlainObject = (obj) => {
+  return _toString.call(obj) === '[object Object]';
+}
+
+/**
+ * Check whether the object has the property.
+ */
+const hasOwnProperty = Object.prototype.hasOwnProperty
+exports.hasOwn = (obj, key) => {
+  return hasOwnProperty.call(obj, key)
+}
+
+/**
+ * Perform no operation.
+ * Stubbing args to make Flow happy without leaving useless transpiled code
+ * with ...rest (https://flow.org/blog/2017/05/07/Strict-Function-Call-Arity/)
+ */
+exports.noop = (a, b, c) => {}
+
+/**
+ * Check if val is a valid array index.
+ */
+exports.isValidArrayIndex = (val) => {
+  const n = parseFloat(String(val))
+  return n >= 0 && Math.floor(n) === n && isFinite(val)
+}

feat: make cropper image clearly