move decorators/methods/ -> decorators/methods

Author: mohayonao

src/decorators/methods.js

@@ -0,0 +1,126 @@
+const repository = new WeakMap();
+
+function createValidator(methodname) {
+  const config = {};
+
+  function validate(...args) {
+    const header = `${this.constructor.name}#${config.methodname}()`;
+    const argErrIndex = argscheck(args, config.parameters);
+
+    if (argErrIndex !== -1) {
+      throw new TypeError(`${header}; argument(${argErrIndex}) should be a ${config.parameters[argErrIndex].validator.name}, but got: ${args[argErrIndex]}`);
+    }
+
+    if (typeof config.precondition === "function") {
+      try {
+        this::config.precondition(...args);
+      } catch (e) {
+        e.message = `${header}; ${e.message}`;
+        throw e;
+      }
+    }
+
+    const res = this::config.methodBody(...args);
+
+    if (typeof config.postcondition === "function") {
+      try {
+        this::config.postcondition(res);
+      } catch (e) {
+        e.message = `${header}; ${e.message}`;
+        throw e;
+      }
+    }
+
+    if (config.returnValue) {
+      if (!config.returnValue.test(res)) {
+        throw new TypeError(`${header}; required a ${config.returnValue.name}, but got ${res}`);
+      }
+    }
+
+    return res;
+  }
+
+  config.methodname = methodname;
+  config.parameters = [];
+  config.descriptor = {
+    value: validate, enumerable: true, configurable: true
+  };
+
+  return config;
+}
+
+function argscheck(values, validators) {
+  for (let i = 0; i < validators.length; i++) {
+    if (validators[i].optional === true && values.length <= i) {
+      break;
+    }
+    if (!validators[i].validator.test(values[i])) {
+      return i;
+    }
+  }
+  return -1;
+}
+
+function getMethodConfig(target, methodname) {
+  let classConfig = repository.get(target);
+
+  if (!classConfig) {
+    repository.set(target, (classConfig = {}));
+  }
+
+  if (!classConfig[methodname]) {
+    classConfig[methodname] = createValidator(methodname);
+  }
+
+  return classConfig[methodname];
+}
+
+export function name($methodname) {
+  return (target, methodname, descriptor) => {
+    const methodConfig = getMethodConfig(target, methodname);
+
+    methodConfig.methodname = $methodname;
+    methodConfig.methodBody = methodConfig.methodBody || descriptor.value;
+
+    return methodConfig.descriptor;
+  };
+}
+
+export function param(paramname, validator) {
+  return (target, methodname, descriptor) => {
+    const methodConfig = getMethodConfig(target, methodname);
+    const optional = /^\[\s*\w+?\s*\]$/.test(paramname);
+
+    if (optional) {
+      paramname = paramname.replace(/^\[|\]$/g, "").trim();
+    }
+
+    methodConfig.parameters.unshift({ paramname, validator, optional });
+    methodConfig.methodBody = methodConfig.methodBody || descriptor.value;
+
+    return methodConfig.descriptor;
+  };
+}
+
+export function returns(validator) {
+  return (target, methodname, descriptor) => {
+    const methodConfig = getMethodConfig(target, methodname);
+
+    methodConfig.returnValue = validator;
+    methodConfig.methodBody = methodConfig.methodBody || descriptor.value;
+
+    return methodConfig.descriptor;
+  };
+}
+
+export function contract({ precondition, postcondition }) {
+  return (target, methodname, descriptor) => {
+    const methodConfig = getMethodConfig(target, methodname);
+
+    methodConfig.precondition = precondition;
+    methodConfig.postcondition = postcondition;
+    methodConfig.methodBody = methodConfig.methodBody || descriptor.value;
+
+    return methodConfig.descriptor;
+  };
+}