45 lines
1.5 KiB
JavaScript
45 lines
1.5 KiB
JavaScript
/* eslint-env node */
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module.exports = {
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meta: {
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type: 'suggestion',
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docs: {
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description: 'Enforce the use of optional object fields',
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category: 'Best Practices',
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recommended: true,
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},
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fixable: 'code',
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schema: [],
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},
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create(context) {
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return {
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'TSPropertySignature > TSTypeAnnotation > TSUnionType': (node) => {
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const types = node.types
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const hasUndefined = types.some((typeNode) => typeNode.type === 'TSUndefinedKeyword')
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if (hasUndefined) {
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const typesWithoutUndefined = types.filter((typeNode) => typeNode.type !== 'TSUndefinedKeyword')
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// If there is more than one type left after removing 'undefined',
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// join them together with ' | ' to create a new union type.
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const newTypeSource =
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typesWithoutUndefined.length > 1
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? typesWithoutUndefined.map((typeNode) => context.getSourceCode().getText(typeNode)).join(' | ')
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: context.getSourceCode().getText(typesWithoutUndefined[0])
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context.report({
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node,
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message: `Prefer optional properties to "Type | undefined".`,
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fix(fixer) {
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const propertySignature = node.parent.parent
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const isAlreadyOptional = propertySignature.optional
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const newTypeAnnotation = isAlreadyOptional ? `: ${newTypeSource}` : `?: ${newTypeSource}`
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return fixer.replaceText(node.parent, newTypeAnnotation)
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},
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})
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}
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},
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}
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},
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}
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