43 lines
2.2 KiB
JavaScript
43 lines
2.2 KiB
JavaScript
// Small function to quickly swap out themes. Gets put into the <head> tag..
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function set_theme_from_local_storage() {
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// Browser does not support Web Storage, bail early.
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if(typeof(window.localStorage) === "undefined") return;
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// Get the user-picked theme from localStorage. May be `null`, which means the default
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// theme.
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var theme = window.localStorage.getItem("documenter-theme");
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// Initialize a few variables for the loop:
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//
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// - active: will contain the index of the theme that should be active. Note that there
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// is no guarantee that localStorage contains sane values. If `active` stays `null`
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// we either could not find the theme or it is the default (primary) theme anyway.
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// Either way, we then need to stick to the primary theme.
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//
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// - disabled: style sheets that should be disabled (i.e. all the theme style sheets
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// that are not the currently active theme)
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var active = null; var disabled = [];
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for (var i = 0; i < document.styleSheets.length; i++) {
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var ss = document.styleSheets[i];
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// The <link> tag of each style sheet is expected to have a data-theme-name attribute
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// which must contain the name of the theme. The names in localStorage much match this.
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var themename = ss.ownerNode.getAttribute("data-theme-name");
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// attribute not set => non-theme stylesheet => ignore
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if(themename === null) continue;
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// To distinguish the default (primary) theme, it needs to have the data-theme-primary
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// attribute set.
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var isprimary = (ss.ownerNode.getAttribute("data-theme-primary") !== null);
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// If we find a matching theme (and it's not the default), we'll set active to non-null
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if(!isprimary && themename === theme) active = i;
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// Store the style sheets of inactive themes so that we could disable them
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if(themename !== theme) disabled.push(ss);
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}
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if(active !== null) {
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// If we did find an active theme, we'll (1) add the theme--$(theme) class to <html>
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document.getElementsByTagName('html')[0].className = "theme--" + theme;
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// and (2) disable all the other theme stylesheets
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disabled.forEach(function(ss){
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ss.disabled = true;
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});
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}
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}
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set_theme_from_local_storage();
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