fix: timeCat type scale setting values caused an error in chart drawing.

.gitignore

@@ -67,8 +67,8 @@ temp
 .DS_Store
 .vscode
 .idea
-#demos/assets/screenshots
 demos/index.html
+demos/assets/screenshots
 demos/debug.html
 
 *.sw*

src/scale/time-cat.js

@@ -111,9 +111,9 @@ class TimeCategory extends Category {
     const rangeMin = this.rangeMin();
     const rangeMax = this.rangeMax();
     const index = this.translate(value);
-    let percent;
 
-    if (this.values.length === 1) {
+    let percent;
+    if (this.values.length === 1 || isNaN(index)) { // is index is NAN should not be set as 0
       percent = index;
     } else if (index > -1) {
       percent = (index) / (this.values.length - 1);

test/unit/scale/cat-spec.js

@@ -168,7 +168,7 @@ describe('scale time cat', function() {
   it('scale', function() {
     expect(scale.scale(1441296000000)).to.be.equal(0);
     expect(scale.scale(2)).to.be.equal(1);
-    expect(scale.scale('2015/10/06')).to.be.equal(0);
+    expect(scale.scale('2015/10/06')).to.be.NaN;
   });
 
   it('invert', function() {
@@ -230,4 +230,13 @@ describe('scale time cat', function() {
     const text = scale.getText('1519084800000');
     expect(text).to.be.equal('time is 1519084800000'); // 原始值
   });
+
+  it('scale scale a value not in scale values', () => {
+    const scale = new Scale.TimeCat({
+      values: [ 1519084800000, 1519171200000, 1519257600000 ]
+    });
+
+    const scaledValue = scale.scale(1441296000000);
+    expect(scaledValue).to.be.NaN;
+  });
 });