Error when exporting layer as png using export

hejie615


                let img = ''
                try {
                    img = sketch.export(layer, {formats: 'png', output: false, includeBackgroundColor: true, includeArtboardBackground: true})
                } catch (e) {
                    console.log(e, layer)
                    break
                }

When I use this code to export an image, I will receive an error message: TypeError: null is not an object (evaluating's. immutableDocument(). clorSpace ')
What is the reason for this? I have set sRGB in the color space, but I still receive an error message indicating this

rodionovd

Does layer exists in a document or is that an object you've created yourself in code and haven't yet added to the document?

Your code works for me, given that I'm exporting a layer selected on the cavas. If that's not your case, please share more code/context.

hejie615

rodionovd
I obtained the entire document and recursively traversed each layer, where the layer represents each layer
My other UI document using this code is valid, but this document will prompt an error. Is it due to document settings
// 数据转换 switch (layer.type) { case 'Image': // console.log('image') // 获取图像的base64表示 const imageBase64 = layer.image.nsdata.base64EncodedStringWithOptions(0); // 将imageBase64属性添加到图像图层中 copy[i].src = 'data:image/png;base64,${imageBase64}'; break case 'ShapePath': case 'Shape': // console.log('shape') try { let svgBuffer = sketch.export(layer, {formats: 'svg', output: false, compact: true, overwriting: true}) copy[i].src = 'data:image/svg+xml;base64,${Buffer.from(svgBuffer).toString('base64')}' } catch (e) { console.log('shape导出失败', e) copy[i].src = '' } // 获取整个层导出图后删除layer copy[i].layers = [] break case 'Slice': // console.log('slice') let img = '' try { img = sketch.export(layer, {formats: 'png', output: false, includeBackgroundColor: true, includeArtboardBackground: true}) } catch (e) { console.log(e, layer) break } copy[i].src = 'data:image/png;base64,${Buffer.from(img).toString('base64')}' // 切片类型获取到切片图片后删除相邻layer只留切片 copy.splice(0, i) copy.splice(1) return; }

hejie615

rodionovd No error will be reported when exporting layers outside of SymbolMaster

rodionovd

hejie615 Yep, this is also a bug in Sketch where children layers of a library symbol (i.e. a symbol that does not belong to any page in a document) are handled a bit differently by the internal export machinery, which leads to errors like this when exporting them via the JS API. I'll report it to Sketch so they can hopefully fix it (or suggested a workaround).

Btw, why do you want to export a slice from a symbol master rather than from an actual instance of that symbol? The former will probably capture the default symbol state anyway without taking any overrides/actual instance content into account.

hejie615

rodionovd I want to obtain the sliceplayer within the symbol instance, but the obtained symbol instance does not have the layers attribute, so I can only obtain the symbolMaster to obtain the layers attribute. Or how to directly obtain a symbol instance and include its layers

rodionovd

hejie615 I think you might want to detach a symbol instance first so it's converted into a regular layer group, which you can iterate as any other layer group, and get direct access to the children layers.

Beware: detaching an instance will remove this instance entirely and replace it with a layer group – so it will modify your document. You may want to create a copy of a symbol instance and detach this copy instead (or just copy the whole document and operate on that copy).

hejie615

rodionovd This is very useful for me, but after using 'duplicate' to copy, it will be directly inserted into the document. Can I not insert the document? Or how to copy the entire document? Will there still be an error when exporting the copied document with a png layer

rodionovd

hejie615 I think you can just call remove() on a duplicated instance to remove it from its parent (and thus from the containing document).

I'm not sure whether it's possible to duplicate a whole document via the JS API. You might have more luck if you just go ahead and copy the document file on disk by saving the current document into a temporary location and then opening this copy instead of using the current document object.

Will there still be an error when exporting the copied document with a png layer

I don't think so given that you recursively detach all symbol instances into layer groups as you iterate your layer tree. The thing is, you'll still have symbol masters in your document but they won't be used anymore so you won't need to export them and thus shouldn't face any of those issues.