(format): move more formatting to Standard style

backport of v1.0.1 addition from 2afaa4d
- not putting in much effort to re-format code that is removed/replaced
  in v1.0.0 however

- remove some semicolons
- more funcs and ifs should have same spacing
- fix some spacing around an assignment

Author: agilgur5

src/index.js

@@ -33,14 +33,14 @@ export default class SignatureCanvas extends Component {
   }
 
   componentDidMount () {
-    this._ctx = this._canvas.getContext("2d");
+    this._ctx = this._canvas.getContext('2d')
 
     this.on()
-    this._resizeCanvas();
+    this._resizeCanvas()
   }
 
-  componentWillUnmount() {
-    this.off();
+  componentWillUnmount () {
+    this.off()
   }
 
   clear = () => {
@@ -100,7 +100,7 @@ export default class SignatureCanvas extends Component {
     /* When zoomed out to less than 100%, for some very strange reason,
       some browsers report devicePixelRatio as less than 1
       and only part of the canvas is cleared then. */
-    let ratio =  Math.max(window.devicePixelRatio || 1, 1)
+    let ratio = Math.max(window.devicePixelRatio || 1, 1)
 
     // only change width/height if none has been passed in as a prop
     if (!width) {
@@ -109,7 +109,7 @@ export default class SignatureCanvas extends Component {
     if (!height) {
       canvas.height = canvas.offsetHeight * ratio
     }
-    if(!width || !height) {
+    if (!width || !height) {
       ctx.scale(ratio, ratio)
       this.clear()
     }