docs: Update README with analyze() options (#111)

Fixes #110

README.md

@@ -26,15 +26,32 @@ To use in a CommonJS file:
 const eslintScope = require('eslint-scope');
 ```
 
+In order to analyze scope, you'll need to have an [ESTree](https://github.com/estree/estree) compliant AST structure to run it on. The primary method is `eslintScope.analyze()`, which takes two arguments:
+
+1. `ast` - the ESTree-compliant AST structure to analyze.
+2. `options` (optional) - Options to adjust how the scope is analyzed, including:
+  * `ignoreEval` (default: `false`) - Set to `true` to ignore all `eval()` calls (which would normally create scopes).
+  * `nodejsScope` (default: `false`) - Set to `true` to create a top-level function scope needed for CommonJS evaluation.
+  * `impliedStrict` (default: `false`) - Set to `true` to evaluate the code in strict mode even outside of modules and without `"use strict"`.
+  * `ecmaVersion` (default: `5`) - The version of ECMAScript to use to evaluate the code.
+  * `sourceType` (default: `"script"`) - The type of JavaScript file to evaluate. Change to `"module"` for ECMAScript module code.
+  * `childVisitorKeys` (default: `null`) - An object with visitor key information (like [`eslint-visitor-keys`](https://github.com/eslint/eslint-visitor-keys)). Without this, `eslint-scope` finds child nodes to visit algorithmically. Providing this option is a performance enhancement.
+  * `fallback` (default: `"iteration"`) - The strategy to use when `childVisitorKeys` is not specified. May be a function.
+
 Example:
 
 ```js
 import * as eslintScope from 'eslint-scope';
 import * as espree from 'espree';
 import estraverse from 'estraverse';
 
-const ast = espree.parse(code, { range: true });
-const scopeManager = eslintScope.analyze(ast);
+const options = {
+    ecmaVersion: 2022,
+    sourceType: "module"
+};
+
+const ast = espree.parse(code, { range: true, ...options });
+const scopeManager = eslintScope.analyze(ast, options);
 
 const currentScope = scopeManager.acquire(ast);   // global scope