/
viewportScale.js
48 lines (34 loc) · 946 Bytes
/
viewportScale.js
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/* Get viewport scale.
*/
/* example
* viewportScale(); // -> 3
*/
/* module
* env: browser
*/
/* typescript
* export declare function viewportScale(): number;
*/
_('meta clamp trim each map isNaN');
exports = function() {
let viewport = meta('viewport');
if (!viewport) return 1;
viewport = map(viewport.split(','), function(val) {
return trim(val);
});
let minScale = 0.25,
maxScale = 5,
initialScale = 1;
each(viewport, function(val) {
val = val.split('=');
const key = val[0];
val = val[1];
if (key === 'initial-scale') initialScale = +val;
if (key === 'maximum-scale') maxScale = +val;
if (key === 'minimum-scale') minScale = +val;
});
const ret = clamp(initialScale, minScale, maxScale);
// Some will use ';' to be the separator, need to avoid the wrong result.
if (isNaN(ret)) return 1;
return ret;
};