121 lines
4 KiB
JavaScript
121 lines
4 KiB
JavaScript
const dbFunctions = ["find", "findBy", "findOne", "findOneBy", "findOneOrFail", "findOneByOrFail", "getOne", "getMany", "getRawOne", "getRawMany"];
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module.exports = {
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meta: {
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type: "suggestion",
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},
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create(context) {
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return {
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"Program:exit"(programNode) {
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const isNull = (node) => node.type === "Literal" && node.value === null;
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const scopes = [context.getScope()];
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while (scopes.length > 0) {
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const s = scopes.pop();
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s.childScopes.forEach(x => scopes.push(x));
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const variables = s.variables
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.filter(x =>
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x.references
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.filter((ref) => ref.isRead())
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.length > 0
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&& x.defs.length > 0
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);
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for (const v of variables) {
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let findValueAssign = null;
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// if the find value was not read, there will already be an unused variable lint
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// or maybe this was inside an if/else so we dont want to cause a false positive
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let read = false;
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for (const ref of v.references) {
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if (
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ref.isWrite()
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) {
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if (!ref.writeExpr) continue;
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let writeExpr = ref.writeExpr;
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// unwrap write expression, order matters to correctly unwrap
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// something like "await Promise.all([a, b])".
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// Basically a poor mans data flow analysis.
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if (writeExpr.type === "AwaitExpression")
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writeExpr = writeExpr.argument;
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if (
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writeExpr.type === "CallExpression"
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&& writeExpr.callee.type === "MemberExpression"
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&& writeExpr.callee.object.type === "Identifier"
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&& writeExpr.callee.object.name === "Promise"
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&& writeExpr.callee.property.type === "Identifier"
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&& writeExpr.callee.property.name === "all"
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)
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writeExpr = writeExpr.arguments[0];
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if (
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writeExpr.type === "ArrayExpression"
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&& ref.identifier.parent.type === "ArrayPattern"
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) {
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// use same index as the index of the identifier in the array pattern
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const index = ref.identifier.parent.elements.indexOf(ref.identifier);
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if (index > -1)
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writeExpr = writeExpr.elements[index];
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}
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// check if this is a DB find thingy
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if (
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writeExpr.type === "CallExpression"
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&& writeExpr.callee.type === "MemberExpression"
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&& writeExpr.callee.property.type === "Identifier"
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&& dbFunctions.includes(writeExpr.callee.property.name)
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) {
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if (findValueAssign && read) {
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context.report({
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node: findValueAssign,
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message: "The returned object(s) are not read from, use `count` or `countBy` instead."
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});
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}
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findValueAssign = writeExpr;
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read = false;
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}
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}
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// must be a read
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else if (findValueAssign) {
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const node = ref.identifier;
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if(!(
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(
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// explicit null check
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node.parent.type === "BinaryExpression" &&
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["==", "===", "!=", "!=="].includes(node.parent.operator) &&
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(
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(isNull(node.parent.left) && node.parent.right === node)
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||
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(isNull(node.parent.right) && node.parent.left === node)
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)
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) || (
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// implicit null check
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["IfStatement", "ConditionalExpression"].includes(node.parent.type)
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) || (
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// different implicit null check
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node.parent.type === "UnaryExpression" &&
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node.parent.operator === "!"
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) || (
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// length check
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node.parent.type === "MemberExpression" &&
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node.parent.object === node &&
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node.parent.property.type === "Identifier" &&
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node.parent.property.name === "length"
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)
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)) {
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// other use, dont report
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findValueAssign = null;
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}
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}
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}
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if (findValueAssign) {
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context.report({
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node: findValueAssign,
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message: "The returned object(s) are not read from, use `count` or `countBy` instead."
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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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};
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