Added replaceTheme function

[kuket15]

to merge the theme passed in with the default theme.

The standard updateTheme function only allows to merge the passed in theme with the current theme.

[codecov]

Codecov Report

Merging #1920 into next will increase coverage by 0.01%.
The diff coverage is 100%.

@@            Coverage Diff            @@
##             next   #1920      +/-   ##
=========================================
+ Coverage   95.88%   95.9%   +0.01%     
=========================================
  Files          34      34              
  Lines         681     683       +2     
  Branches       73      73              
=========================================
+ Hits          653     655       +2     
  Misses         24      24              
  Partials        4       4

Impacted Files	Coverage Δ
src/config/ThemeProvider.js	100% <100%> (ø)	⬆️
src/config/withTheme.js	100% <100%> (ø)	⬆️

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[iRoachie]

What’s the benefit of adding this? Since it does a merge can’t you specify the properties you want to override?

[kuket15]

In my app I need to completely replace the current theme with a new one.
The standard updateTheme does a merge, so it keeps the existing properties that I don't overwrite.

E.g.

var currentTheme = {
    Button: {
      containerStyle: {
        marginHorizontal: 20,
        marginVertical: 10,
      },
      titleStyle: {
        color: 'rgb(255,255,255)',
        fontFamily: 'regular',
        fontSize: 16,
      },
    },
}

var newTheme = {
    Button: {
      containerStyle: {
        marginHorizontal: 50,
        marginVertical: 20,
      },
    },
}

In this case the updateTheme function would keep the titleStyle properties in the updated theme. I don't want to manually set the titleStyle properties to the default values for the Button component.