diff --git a/common/index.js b/common/index.js
index 6c7436e4..9a7afec7 100644
--- a/common/index.js
+++ b/common/index.js
@@ -1,5 +1,5 @@
 const utils = require('../utils');
-const number_format = require('../utils/number_format');
+const numberFormat = require('../utils/numberFormat');
 const format = require('../utils/format');
 const errors = require('./errors');
 const BaseDocument = require('frappejs/model/document');
@@ -8,7 +8,7 @@ const BaseMeta = require('frappejs/model/meta');
 module.exports = {
     initLibs(frappe) {
         Object.assign(frappe, utils);
-        Object.assign(frappe, number_format);
+        Object.assign(frappe, numberFormat);
         Object.assign(frappe, format);
         frappe.errors = errors;
         frappe.BaseDocument = BaseDocument;
diff --git a/index.js b/index.js
index fea81439..252a3626 100644
--- a/index.js
+++ b/index.js
@@ -1,9 +1,11 @@
+const Observable = require('./utils/observable');
 
 module.exports = {
     async init() {
         if (this._initialized) return;
         this.initConfig();
         this.initGlobals();
+        this.docs = new Observable();
         this._initialized = true;
     },
 
diff --git a/tests/test_utils.js b/tests/test_utils.js
index 4a505c84..0dc51f9a 100644
--- a/tests/test_utils.js
+++ b/tests/test_utils.js
@@ -1,35 +1,35 @@
-const number_format = require('frappejs/utils/number_format');
+const numberFormat = require('frappejs/utils/numberFormat');
 const assert = require('assert');
 
 describe('Number Formatting', () => {
     it('should format numbers', () => {
-        assert.equal(number_format.format_number(100), '100.00');
-        assert.equal(number_format.format_number(1000), '1,000.00');
-        assert.equal(number_format.format_number(10000), '10,000.00');
-        assert.equal(number_format.format_number(100000), '100,000.00');
-        assert.equal(number_format.format_number(1000000), '1,000,000.00');
-        assert.equal(number_format.format_number(100.1234), '100.12');
-        assert.equal(number_format.format_number(1000.1234), '1,000.12');
+        assert.equal(numberFormat.formatNumber(100), '100.00');
+        assert.equal(numberFormat.formatNumber(1000), '1,000.00');
+        assert.equal(numberFormat.formatNumber(10000), '10,000.00');
+        assert.equal(numberFormat.formatNumber(100000), '100,000.00');
+        assert.equal(numberFormat.formatNumber(1000000), '1,000,000.00');
+        assert.equal(numberFormat.formatNumber(100.1234), '100.12');
+        assert.equal(numberFormat.formatNumber(1000.1234), '1,000.12');
     });
 
     it('should parse numbers', () => {
-        assert.equal(number_format.parse_number('100.00'), 100);
-        assert.equal(number_format.parse_number('1,000.00'), 1000);
-        assert.equal(number_format.parse_number('10,000.00'), 10000);
-        assert.equal(number_format.parse_number('100,000.00'), 100000);
-        assert.equal(number_format.parse_number('1,000,000.00'), 1000000);
-        assert.equal(number_format.parse_number('100.1234'), 100.1234);
-        assert.equal(number_format.parse_number('1,000.1234'), 1000.1234);
+        assert.equal(numberFormat.parseNumber('100.00'), 100);
+        assert.equal(numberFormat.parseNumber('1,000.00'), 1000);
+        assert.equal(numberFormat.parseNumber('10,000.00'), 10000);
+        assert.equal(numberFormat.parseNumber('100,000.00'), 100000);
+        assert.equal(numberFormat.parseNumber('1,000,000.00'), 1000000);
+        assert.equal(numberFormat.parseNumber('100.1234'), 100.1234);
+        assert.equal(numberFormat.parseNumber('1,000.1234'), 1000.1234);
     });
 
     it('should format lakhs and crores', () => {
-        assert.equal(number_format.format_number(100, '#,##,###.##'), '100.00');
-        assert.equal(number_format.format_number(1000, '#,##,###.##'), '1,000.00');
-        assert.equal(number_format.format_number(10000, '#,##,###.##'), '10,000.00');
-        assert.equal(number_format.format_number(100000, '#,##,###.##'), '1,00,000.00');
-        assert.equal(number_format.format_number(1000000, '#,##,###.##'), '10,00,000.00');
-        assert.equal(number_format.format_number(10000000, '#,##,###.##'), '1,00,00,000.00');
-        assert.equal(number_format.format_number(100.1234, '#,##,###.##'), '100.12');
-        assert.equal(number_format.format_number(1000.1234, '#,##,###.##'), '1,000.12');
+        assert.equal(numberFormat.formatNumber(100, '#,##,###.##'), '100.00');
+        assert.equal(numberFormat.formatNumber(1000, '#,##,###.##'), '1,000.00');
+        assert.equal(numberFormat.formatNumber(10000, '#,##,###.##'), '10,000.00');
+        assert.equal(numberFormat.formatNumber(100000, '#,##,###.##'), '1,00,000.00');
+        assert.equal(numberFormat.formatNumber(1000000, '#,##,###.##'), '10,00,000.00');
+        assert.equal(numberFormat.formatNumber(10000000, '#,##,###.##'), '1,00,00,000.00');
+        assert.equal(numberFormat.formatNumber(100.1234, '#,##,###.##'), '100.12');
+        assert.equal(numberFormat.formatNumber(1000.1234, '#,##,###.##'), '1,000.12');
     });
 });
\ No newline at end of file
diff --git a/utils/format.js b/utils/format.js
index 2fb84c1f..95f55fc8 100644
--- a/utils/format.js
+++ b/utils/format.js
@@ -1,4 +1,4 @@
-const number_format = require('./number_format');
+const numberFormat = require('./numberFormat');
 const markdown = new (require('showdown').Converter)();
 const moment = require('moment');
 const frappe = require('frappejs');
@@ -10,7 +10,7 @@ module.exports = {
         }
 
         if (field.fieldtype === 'Currency') {
-            value = number_format.format_number(value);
+            value = numberFormat.formatNumber(value);
 
         } else if (field.fieldtype === 'Text') {
             value = markdown.makeHtml(value || '');
diff --git a/utils/numberFormat.js b/utils/numberFormat.js
new file mode 100644
index 00000000..24b40735
--- /dev/null
+++ b/utils/numberFormat.js
@@ -0,0 +1,104 @@
+const numberFormats = {
+  "#,###.##": { fractionSep: ".", groupSep: ",", precision: 2 },
+  "#.###,##": { fractionSep: ",", groupSep: ".", precision: 2 },
+  "# ###.##": { fractionSep: ".", groupSep: " ", precision: 2 },
+  "# ###,##": { fractionSep: ",", groupSep: " ", precision: 2 },
+  "#'###.##": { fractionSep: ".", groupSep: "'", precision: 2 },
+  "#, ###.##": { fractionSep: ".", groupSep: ", ", precision: 2 },
+  "#,##,###.##": { fractionSep: ".", groupSep: ",", precision: 2 },
+  "#,###.###": { fractionSep: ".", groupSep: ",", precision: 3 },
+  "#.###": { fractionSep: "", groupSep: ".", precision: 0 },
+  "#,###": { fractionSep: "", groupSep: ",", precision: 0 },
+}
+
+module.exports = {
+  // parse a formatted number string
+  // from "4,555,000.34" -> 4555000.34
+  parseNumber(number, format = '#,###.##') {
+    if (!number) {
+      return 0;
+    }
+    if (typeof number === 'number') {
+      return number;
+    }
+    const info = this.getFormatInfo(format);
+    return parseFloat(this.removeSeparator(number, info.groupSep));
+  },
+
+  formatNumber(number, format = '#,###.##', precision = null) {
+    if (!number) {
+      number = 0;
+    }
+    let info = this.getFormatInfo(format);
+    if (precision) {
+      info.precision = precision;
+    }
+    let is_negative = false;
+
+    number = this.parseNumber(number);
+    if (number < 0) {
+      is_negative = true;
+    }
+    number = Math.abs(number);
+    number = number.toFixed(info.precision);
+
+    var parts = number.split('.');
+
+    // get group position and parts
+    var group_position = info.groupSep ? 3 : 0;
+
+    if (group_position) {
+      var integer = parts[0];
+      var str = '';
+
+      for (var i = integer.length; i >= 0; i--) {
+        var l = this.removeSeparator(str, info.groupSep).length;
+        if (format == "#,##,###.##" && str.indexOf(",") != -1) { // INR
+          group_position = 2;
+          l += 1;
+        }
+
+        str += integer.charAt(i);
+
+        if (l && !((l + 1) % group_position) && i != 0) {
+          str += info.groupSep;
+        }
+      }
+      parts[0] = str.split("").reverse().join("");
+    }
+    if (parts[0] + "" == "") {
+      parts[0] = "0";
+    }
+
+    // join decimal
+    parts[1] = (parts[1] && info.fractionSep) ? (info.fractionSep + parts[1]) : "";
+
+    // join
+    return (is_negative ? "-" : "") + parts[0] + parts[1];
+  },
+
+  getFormatInfo(format) {
+    let format_info = numberFormats[format];
+
+    if (!format_info) {
+      throw `Unknown number format "${format}"`;
+    }
+
+    return format_info;
+  },
+
+  round(num, precision) {
+    var is_negative = num < 0 ? true : false;
+    var d = parseInt(precision || 0);
+    var m = Math.pow(10, d);
+    var n = +(d ? Math.abs(num) * m : Math.abs(num)).toFixed(8); // Avoid rounding errors
+    var i = Math.floor(n), f = n - i;
+    var r = ((!precision && f == 0.5) ? ((i % 2 == 0) ? i : i + 1) : Math.round(n));
+    r = d ? r / m : r;
+    return is_negative ? -r : r;
+  },
+
+  removeSeparator(text, sep) {
+    return text.replace(new RegExp(sep === "." ? "\\." : sep, "g"), '');
+  }
+};
diff --git a/utils/number_format.js b/utils/number_format.js
deleted file mode 100644
index 95839dca..00000000
--- a/utils/number_format.js
+++ /dev/null
@@ -1,104 +0,0 @@
-const number_formats = {
-    "#,###.##": { fraction_sep: ".", group_sep: ",", precision: 2 },
-    "#.###,##": { fraction_sep: ",", group_sep: ".", precision: 2 },
-    "# ###.##": { fraction_sep: ".", group_sep: " ", precision: 2 },
-    "# ###,##": { fraction_sep: ",", group_sep: " ", precision: 2 },
-    "#'###.##": { fraction_sep: ".", group_sep: "'", precision: 2 },
-    "#, ###.##": { fraction_sep: ".", group_sep: ", ", precision: 2 },
-    "#,##,###.##": { fraction_sep: ".", group_sep: ",", precision: 2 },
-    "#,###.###": { fraction_sep: ".", group_sep: ",", precision: 3 },
-    "#.###": { fraction_sep: "", group_sep: ".", precision: 0 },
-    "#,###": { fraction_sep: "", group_sep: ",", precision: 0 },
-}
-
-module.exports = {
-    // parse a formatted number string
-    // from "4,555,000.34" -> 4555000.34
-    parse_number(number, format='#,###.##') {
-        if (!number) {
-            return 0;
-        }
-        if (typeof number === 'number') {
-            return number;
-        }
-        const info = this.get_format_info(format);
-        return parseFloat(this.remove_separator(number, info.group_sep));
-    },
-
-    format_number(number, format = '#,###.##', precision = null) {
-        if (!number) {
-            number = 0;
-        }
-        let info = this.get_format_info(format);
-        if (precision) {
-            info.precision = precision;
-        }
-        let is_negative = false;
-
-        number = this.parse_number(number);
-        if (number < 0) {
-            is_negative = true;
-        }
-        number = Math.abs(number);
-        number = number.toFixed(info.precision);
-
-        var parts = number.split('.');
-
-        // get group position and parts
-        var group_position = info.group_sep ? 3 : 0;
-
-        if (group_position) {
-            var integer = parts[0];
-            var str = '';
-            var offset = integer.length % group_position;
-            for (var i = integer.length; i >= 0; i--) {
-                var l = this.remove_separator(str, info.group_sep).length;
-                if (format == "#,##,###.##" && str.indexOf(",") != -1) { // INR
-                    group_position = 2;
-                    l += 1;
-                }
-
-                str += integer.charAt(i);
-
-                if (l && !((l + 1) % group_position) && i != 0) {
-                    str += info.group_sep;
-                }
-            }
-            parts[0] = str.split("").reverse().join("");
-        }
-        if (parts[0] + "" == "") {
-            parts[0] = "0";
-        }
-
-        // join decimal
-        parts[1] = (parts[1] && info.fraction_sep) ? (info.fraction_sep + parts[1]) : "";
-
-        // join
-        return (is_negative ? "-" : "") + parts[0] + parts[1];
-    },
-
-    get_format_info(format) {
-        let format_info = number_formats[format];
-
-        if (!format_info) {
-            throw `Unknown number format "${format}"`;
-        }
-
-        return format_info;
-    },
-
-    round(num, precision) {
-        var is_negative = num < 0 ? true : false;
-        var d = parseInt(precision || 0);
-        var m = Math.pow(10, d);
-        var n = +(d ? Math.abs(num) * m : Math.abs(num)).toFixed(8); // Avoid rounding errors
-        var i = Math.floor(n), f = n - i;
-        var r = ((!precision && f == 0.5) ? ((i % 2 == 0) ? i : i + 1) : Math.round(n));
-        r = d ? r / m : r;
-        return is_negative ? -r : r;
-    },
-
-    remove_separator(text, sep) {
-        return text.replace(new RegExp(sep === "." ? "\\." : sep, "g"), '');
-    }
-};