html2canvas/src/Feature.js

/* @flow */
'use strict';

const testRangeBounds = document => {
    const TEST_HEIGHT = 123;

    if (document.createRange) {
        const range = document.createRange();
        if (range.getBoundingClientRect) {
            const testElement = document.createElement('boundtest');
            testElement.style.height = `${TEST_HEIGHT}px`;
            testElement.style.display = 'block';
            document.body.appendChild(testElement);

            range.selectNode(testElement);
            const rangeBounds = range.getBoundingClientRect();
            const rangeHeight = Math.round(rangeBounds.height);
            document.body.removeChild(testElement);
            if (rangeHeight === TEST_HEIGHT) {
                return true;
            }
        }
    }

    return false;
};

const FEATURES = {
    // $FlowFixMe - get/set properties not yet supported
    get SUPPORT_RANGE_BOUNDS() {
        'use strict';
        const value = testRangeBounds(document);
        Object.defineProperty(FEATURES, 'SUPPORT_RANGE_BOUNDS', {value});
        return value;
    }
};

export default FEATURES;