added js api

.babelrc

@@ -0,0 +1,15 @@
+{
+  "plugins": ["@babel/plugin-transform-classes"],
+  "presets": [
+    [
+      "@babel/preset-env",
+      {
+        "targets": {
+          "ie": "11"
+        },
+        "useBuiltIns": "usage",
+        "corejs": 3
+      }
+    ]
+  ]
+}

.eslintignore

@@ -0,0 +1,3 @@
+/node_modules/
+/docs
+/dist

.eslintrc.js

@@ -0,0 +1,91 @@
+module.exports = {
+  env: {
+    browser: true,
+    commonjs: true,
+    es6: true,
+    node: true,
+    mocha: true,
+  },
+  extends: ['eslint:recommended'],
+  parserOptions: {
+    ecmaVersion: 2018,
+    sourceType: 'module',
+  },
+  rules: {
+    'array-callback-return': ['error'],
+    'quote-props': ['error', 'as-needed'],
+    'arrow-parens': ['error', 'as-needed'],
+    'arrow-spacing': ['error', { before: true, after: true }],
+    'brace-style': ['error', '1tbs', { allowSingleLine: true }],
+    'comma-spacing': ['error', { before: false, after: true }],
+    'comma-dangle': [
+      'error',
+      {
+        arrays: 'always-multiline',
+        objects: 'always-multiline',
+        imports: 'always-multiline',
+        exports: 'always-multiline',
+        functions: 'always-multiline',
+      },
+    ],
+    eqeqeq: ['error', 'always'],
+    indent: ['error', 2, { SwitchCase: 1 }],
+    'jsx-quotes': ['error', 'prefer-double'],
+    'valid-jsdoc': ['off'],
+    'key-spacing': ['off'],
+    'keyword-spacing': ['error'],
+    'linebreak-style': ['error', 'unix'],
+    'no-dupe-args': ['error'],
+    'no-console': ['warn'],
+    'no-const-assign': ['error'],
+    'no-irregular-whitespace': [
+      'error',
+      {
+        skipStrings: true,
+        skipComments: true,
+        skipRegExps: true,
+        skipTemplates: true,
+      },
+    ],
+    'no-unused-vars': ['error'],
+    'no-undefined': ['error'],
+    'no-var': ['error'],
+    'no-multiple-empty-lines': ['error'],
+    'object-curly-spacing': ['error', 'always'],
+    'require-jsdoc': [
+      'off',
+      {
+        require: {
+          ArrowFunctionExpression: true,
+          ClassDeclaration: true,
+          FunctionDeclaration: true,
+          MethodDefinition: true,
+        },
+      },
+    ],
+    quotes: ['error', 'single'],
+    semi: ['error', 'never'],
+    'spaced-comment': [
+      'error',
+      'always',
+      {
+        line: {
+          markers: ['/'],
+          exceptions: ['-', '+'],
+        },
+        block: {
+          markers: ['!'],
+          exceptions: ['*'],
+          balanced: true,
+        },
+      },
+    ],
+    'space-before-blocks': [
+      'error',
+      { functions: 'always', keywords: 'always', classes: 'always' },
+    ],
+    'space-unary-ops': ['error'],
+    'space-infix-ops': ['error', { int32Hint: false }],
+    'sort-imports': ['off'],
+  },
+}