CasperSecurity
'use strict';
const {
querySelector,
closestByName,
detachNodeFromParent,
} = require('../lib/xast.js');
const { collectStylesheet, computeStyle } = require('../lib/style.js');
const { parsePathData } = require('../lib/path.js');
exports.name = 'removeHiddenElems';
exports.type = 'visitor';
exports.active = true;
exports.description =
'removes hidden elements (zero sized, with absent attributes)';
/**
* Remove hidden elements with disabled rendering:
* - display="none"
* - opacity="0"
* - circle with zero radius
* - ellipse with zero x-axis or y-axis radius
* - rectangle with zero width or height
* - pattern with zero width or height
* - image with zero width or height
* - path with empty data
* - polyline with empty points
* - polygon with empty points
*
* @author Kir Belevich
*
* @type {import('../lib/types').Plugin<{
* isHidden: boolean,
* displayNone: boolean,
* opacity0: boolean,
* circleR0: boolean,
* ellipseRX0: boolean,
* ellipseRY0: boolean,
* rectWidth0: boolean,
* rectHeight0: boolean,
* patternWidth0: boolean,
* patternHeight0: boolean,
* imageWidth0: boolean,
* imageHeight0: boolean,
* pathEmptyD: boolean,
* polylineEmptyPoints: boolean,
* polygonEmptyPoints: boolean,
* }>}
*/
exports.fn = (root, params) => {
const {
isHidden = true,
displayNone = true,
opacity0 = true,
circleR0 = true,
ellipseRX0 = true,
ellipseRY0 = true,
rectWidth0 = true,
rectHeight0 = true,
patternWidth0 = true,
patternHeight0 = true,
imageWidth0 = true,
imageHeight0 = true,
pathEmptyD = true,
polylineEmptyPoints = true,
polygonEmptyPoints = true,
} = params;
const stylesheet = collectStylesheet(root);
return {
element: {
enter: (node, parentNode) => {
// Removes hidden elements
// https://www.w3schools.com/cssref/pr_class_visibility.asp
const computedStyle = computeStyle(stylesheet, node);
if (
isHidden &&
computedStyle.visibility &&
computedStyle.visibility.type === 'static' &&
computedStyle.visibility.value === 'hidden' &&
// keep if any descendant enables visibility
querySelector(node, '[visibility=visible]') == null
) {
detachNodeFromParent(node, parentNode);
return;
}
// display="none"
//
// https://www.w3.org/TR/SVG11/painting.html#DisplayProperty
// "A value of display: none indicates that the given element
// and its children shall not be rendered directly"
if (
displayNone &&
computedStyle.display &&
computedStyle.display.type === 'static' &&
computedStyle.display.value === 'none' &&
// markers with display: none still rendered
node.name !== 'marker'
) {
detachNodeFromParent(node, parentNode);
return;
}
// opacity="0"
//
// https://www.w3.org/TR/SVG11/masking.html#ObjectAndGroupOpacityProperties
if (
opacity0 &&
computedStyle.opacity &&
computedStyle.opacity.type === 'static' &&
computedStyle.opacity.value === '0' &&
// transparent element inside clipPath still affect clipped elements
closestByName(node, 'clipPath') == null
) {
detachNodeFromParent(node, parentNode);
return;
}
// Circles with zero radius
//
// https://www.w3.org/TR/SVG11/shapes.html#CircleElementRAttribute
// "A value of zero disables rendering of the element"
//
// <circle r="0">
if (
circleR0 &&
node.name === 'circle' &&
node.children.length === 0 &&
node.attributes.r === '0'
) {
detachNodeFromParent(node, parentNode);
return;
}
// Ellipse with zero x-axis radius
//
// https://www.w3.org/TR/SVG11/shapes.html#EllipseElementRXAttribute
// "A value of zero disables rendering of the element"
//
// <ellipse rx="0">
if (
ellipseRX0 &&
node.name === 'ellipse' &&
node.children.length === 0 &&
node.attributes.rx === '0'
) {
detachNodeFromParent(node, parentNode);
return;
}
// Ellipse with zero y-axis radius
//
// https://www.w3.org/TR/SVG11/shapes.html#EllipseElementRYAttribute
// "A value of zero disables rendering of the element"
//
// <ellipse ry="0">
if (
ellipseRY0 &&
node.name === 'ellipse' &&
node.children.length === 0 &&
node.attributes.ry === '0'
) {
detachNodeFromParent(node, parentNode);
return;
}
// Rectangle with zero width
//
// https://www.w3.org/TR/SVG11/shapes.html#RectElementWidthAttribute
// "A value of zero disables rendering of the element"
//
// <rect width="0">
if (
rectWidth0 &&
node.name === 'rect' &&
node.children.length === 0 &&
node.attributes.width === '0'
) {
detachNodeFromParent(node, parentNode);
return;
}
// Rectangle with zero height
//
// https://www.w3.org/TR/SVG11/shapes.html#RectElementHeightAttribute
// "A value of zero disables rendering of the element"
//
// <rect height="0">
if (
rectHeight0 &&
rectWidth0 &&
node.name === 'rect' &&
node.children.length === 0 &&
node.attributes.height === '0'
) {
detachNodeFromParent(node, parentNode);
return;
}
// Pattern with zero width
//
// https://www.w3.org/TR/SVG11/pservers.html#PatternElementWidthAttribute
// "A value of zero disables rendering of the element (i.e., no paint is applied)"
//
// <pattern width="0">
if (
patternWidth0 &&
node.name === 'pattern' &&
node.attributes.width === '0'
) {
detachNodeFromParent(node, parentNode);
return;
}
// Pattern with zero height
//
// https://www.w3.org/TR/SVG11/pservers.html#PatternElementHeightAttribute
// "A value of zero disables rendering of the element (i.e., no paint is applied)"
//
// <pattern height="0">
if (
patternHeight0 &&
node.name === 'pattern' &&
node.attributes.height === '0'
) {
detachNodeFromParent(node, parentNode);
return;
}
// Image with zero width
//
// https://www.w3.org/TR/SVG11/struct.html#ImageElementWidthAttribute
// "A value of zero disables rendering of the element"
//
// <image width="0">
if (
imageWidth0 &&
node.name === 'image' &&
node.attributes.width === '0'
) {
detachNodeFromParent(node, parentNode);
return;
}
// Image with zero height
//
// https://www.w3.org/TR/SVG11/struct.html#ImageElementHeightAttribute
// "A value of zero disables rendering of the element"
//
// <image height="0">
if (
imageHeight0 &&
node.name === 'image' &&
node.attributes.height === '0'
) {
detachNodeFromParent(node, parentNode);
return;
}
// Path with empty data
//
// https://www.w3.org/TR/SVG11/paths.html#DAttribute
//
// <path d=""/>
if (pathEmptyD && node.name === 'path') {
if (node.attributes.d == null) {
detachNodeFromParent(node, parentNode);
return;
}
const pathData = parsePathData(node.attributes.d);
if (pathData.length === 0) {
detachNodeFromParent(node, parentNode);
return;
}
// keep single point paths for markers
if (
pathData.length === 1 &&
computedStyle['marker-start'] == null &&
computedStyle['marker-end'] == null
) {
detachNodeFromParent(node, parentNode);
return;
}
return;
}
// Polyline with empty points
//
// https://www.w3.org/TR/SVG11/shapes.html#PolylineElementPointsAttribute
//
// <polyline points="">
if (
polylineEmptyPoints &&
node.name === 'polyline' &&
node.attributes.points == null
) {
detachNodeFromParent(node, parentNode);
return;
}
// Polygon with empty points
//
// https://www.w3.org/TR/SVG11/shapes.html#PolygonElementPointsAttribute
//
// <polygon points="">
if (
polygonEmptyPoints &&
node.name === 'polygon' &&
node.attributes.points == null
) {
detachNodeFromParent(node, parentNode);
return;
}
},
},
};
};