diff --git a/elements/Pattern.js b/elements/Pattern.js
index 862f19ec..21a18f6c 100644
--- a/elements/Pattern.js
+++ b/elements/Pattern.js
@@ -5,7 +5,7 @@ import { numberProp } from "../lib/props";
 import PATTERN_UNITS from "../lib/PATTERN_UNITS";
 import { PatternAttributes } from "../lib/attributes";
 import extractTransform from "../lib/extract/extractTransform";
-import extractViewBox from "react-native-svg/lib/extract/extractViewBox";
+import extractViewBox from "../lib/extract/extractViewBox";
 
 export default class extends Component {
     static displayName = "Pattern";
diff --git a/lib/attributes.js b/lib/attributes.js
index a21b6efb..06489029 100644
--- a/lib/attributes.js
+++ b/lib/attributes.js
@@ -99,8 +99,6 @@ const UseAttributes = {
     href: true,
     width: true,
     height: true,
-    usewidth: true,
-    useheight: true,
 };
 
 const SymbolAttributes = {
@@ -171,8 +169,6 @@ const PatternAttributes = {
     y: true,
     width: true,
     height: true,
-    patternwidth: true,
-    patternheight: true,
     patternUnits: true,
     patternContentUnits: true,
     patternTransform: {
@@ -186,8 +182,6 @@ const MaskAttributes = {
     y: true,
     width: true,
     height: true,
-    maskwidth: true,
-    maskheight: true,
     maskUnits: true,
     maskContentUnits: true,
     maskTransform: {
@@ -235,8 +229,6 @@ const ImageAttributes = {
     y: true,
     width: true,
     height: true,
-    imagewidth: true,
-    imageheight: true,
     src: true,
     align: true,
     meetOrSlice: true
@@ -256,8 +248,6 @@ const RectAttributes = {
     y: true,
     width: true,
     height: true,
-    rectwidth: true,
-    rectheight: true,
     rx: true,
     ry: true
 };
diff --git a/lib/extract/extractBrush.js b/lib/extract/extractBrush.js
index b1625756..551702a6 100644
--- a/lib/extract/extractBrush.js
+++ b/lib/extract/extractBrush.js
@@ -10,14 +10,14 @@ export default function(colorOrBrush) {
         return [2];
     }
     try {
-        let matched = colorOrBrush.match(patternReg);
+        const matched = colorOrBrush.match(patternReg);
         // brush
         if (matched) {
             return [1, matched[1]];
             //todo:
         } else {
             // solid color
-            let [r, g, b, a = 1] = Color(colorOrBrush)
+            const [r, g, b, a = 1] = Color(colorOrBrush)
                 .rgb()
                 .array();
             return [0, r / 255, g / 255, b / 255, a];
diff --git a/lib/extract/extractClipPath.js b/lib/extract/extractClipPath.js
index c59ae52e..a9539e3e 100644
--- a/lib/extract/extractClipPath.js
+++ b/lib/extract/extractClipPath.js
@@ -6,13 +6,13 @@ const clipRules = {
 };
 
 export default function(props) {
-    let { clipPath, clipRule } = props;
-    let clipPathProps = {};
+    const { clipPath, clipRule } = props;
+    const clipPathProps = {};
 
     if (clipPath) {
         clipPathProps.clipRule = clipRules[clipRule] === 0 ? 0 : 1;
 
-        let matched = clipPath.match(clipReg);
+        const matched = clipPath.match(clipReg);
 
         if (matched) {
             clipPathProps.clipPath = matched[1];
diff --git a/lib/extract/extractGradient.js b/lib/extract/extractGradient.js
index 87e10395..4534b573 100644
--- a/lib/extract/extractGradient.js
+++ b/lib/extract/extractGradient.js
@@ -16,7 +16,7 @@ export default function(props) {
     Children.forEach(props.children, child => {
         if (child.props.stopColor && child.props.offset) {
             // convert percent to float.
-            let offset = percentToFloat(child.props.offset);
+            const offset = percentToFloat(child.props.offset);
 
             // add stop
             //noinspection JSUnresolvedFunction
@@ -36,7 +36,7 @@ export default function(props) {
     const gradient = [];
 
     sorted.forEach(({ stop }) => {
-        let [r, g, b, a = 1] = stop.rgb().array();
+        const [r, g, b, a = 1] = stop.rgb().array();
         gradient.push(r / 255);
         gradient.push(g / 255);
         gradient.push(b / 255);
diff --git a/lib/extract/extractProps.js b/lib/extract/extractProps.js
index a2e4d6ab..bdaf283b 100644
--- a/lib/extract/extractProps.js
+++ b/lib/extract/extractProps.js
@@ -26,7 +26,7 @@ export default function(prop, ref) {
     }
 
     if (mask) {
-        let matched = mask.match(urlRegex);
+        const matched = mask.match(urlRegex);
 
         if (matched) {
             extractedProps.mask = matched[1];
diff --git a/lib/extract/extractTransform.js b/lib/extract/extractTransform.js
index 3143b9a4..9c777dce 100644
--- a/lib/extract/extractTransform.js
+++ b/lib/extract/extractTransform.js
@@ -1,7 +1,8 @@
 import Matrix2D from "../Matrix2D";
-import _ from "lodash";
-let pooledMatrix = new Matrix2D();
 import peg from "pegjs";
+import _ from "lodash";
+
+const pooledMatrix = new Matrix2D();
 
 function transformToMatrix(props, transform) {
     pooledMatrix.reset();
@@ -228,19 +229,19 @@ export function props2transform(props) {
     if (props && typeof props === "string") {
         return props;
     }
-    let [originX, originY] = universal2axis(
+    const [originX, originY] = universal2axis(
         props.origin,
         props.originX,
         props.originY,
     );
-    let [scaleX, scaleY] = universal2axis(
+    const [scaleX, scaleY] = universal2axis(
         props.scale,
         props.scaleX,
         props.scaleY,
         1,
     );
-    let [skewX, skewY] = universal2axis(props.skew, props.skewX, props.skewY);
-    let [translateX, translateY] = universal2axis(
+    const [skewX, skewY] = universal2axis(props.skew, props.skewX, props.skewY);
+    const [translateX, translateY] = universal2axis(
         props.translate,
         _.isNil(props.translateX) ? props.x || 0 : props.translateX,
         _.isNil(props.translateY) ? props.y || 0 : props.translateY,
diff --git a/lib/extract/extractViewBox.js b/lib/extract/extractViewBox.js
index 8a366a23..0eb8b10f 100644
--- a/lib/extract/extractViewBox.js
+++ b/lib/extract/extractViewBox.js
@@ -29,19 +29,19 @@ export default function(props) {
         return null;
     }
 
-    let params = viewBox.trim().split(spacesRegExp);
+    const params = viewBox.trim().split(spacesRegExp);
 
-    if (params.length === 4 && params.every(param => !isNaN(+params))) {
+    if (params.length === 4 && params.every(param => !isNaN(+param))) {
         console.warn("Invalid `viewBox` prop:" + viewBox);
         return null;
     }
 
-    let modes = preserveAspectRatio
+    const modes = preserveAspectRatio
         ? preserveAspectRatio.trim().split(spacesRegExp)
         : [];
 
-    let meetOrSlice = meetOrSliceTypes[modes[1]] || 0;
-    let align = alignEnum[modes[0]] || "xMidYMid";
+    const meetOrSlice = meetOrSliceTypes[modes[1]] || 0;
+    const align = alignEnum[modes[0]] || "xMidYMid";
 
     return {
         minX: +params[0],
diff --git a/lib/percentToFloat.js b/lib/percentToFloat.js
index 3886fad6..32678dbd 100644
--- a/lib/percentToFloat.js
+++ b/lib/percentToFloat.js
@@ -1,6 +1,6 @@
-let percentReg = /^([+\-]?\d+(?:\.\d+)?(?:[eE][+\-]?\d+)?)(%?)$/;
+const percentReg = /^([+\-]?\d+(?:\.\d+)?(?:[eE][+\-]?\d+)?)(%?)$/;
 export default function(percent) {
-    let matched = percent.match(percentReg);
+    const matched = percent.match(percentReg);
     if (!matched) {
         console.warn(
             `\`${percent}\` is not a valid number or percentage string.`