variablestore v0.1.7

VariableStore

A variable data store using to privately store variables using a map like interface.

const regex    = /^[a-zA-Z\_]\w*$/;
const restrictedNames = ["ans"];
const varStore = new VariableStore(regex, restrictedNames);

varStore.set({name: "a1", value: 2});
if(varStore.has("a1")) {
   console.log(varStore.get("a1")); // 2
}

try {
   varStore.set({name: "1a", value: 2});
} catch(e) {
   console.log(e.message) // Must satisfy regex
}

try {
   varStore.set({name: "ans", value: 2});
} catch(e) {
   console.log(e.message); // Variable cannot be reserved word
}

Installing

npm install variablestore

Main Example

Setup.

// Initialize your rejex and restrictedNames, and create a new varStore
const regex    = /^[a-zA-Z\_]\w*$/;
const restrictedNames = ["ans"];
const varStore = new VariableStore(regex, restrictedNames);

Add variables to data store.

// Variables can be added to VariableStore with set, of the form
const varObj = {name: "a", value: "b"};
varStore.set(varObj);

// Variable names that violate the regex passed will throw error
try {
   varStore.set({name:"1a", value: "b"});
} catch(e) {
   console.log(e.message); // Invalid variable name, must satisfy regex
}

Check for membership, and return value from VariableStore.

// Can see if VariableStore has variable with has
console.log(varStore.has("a")); // true

// Can get variable from VariableStore with get
console.log(varStore.get("a")); // b

Retrieve all variable names or variable objects.

// Add another variable
varStore.set({name: "b", value: "b"}); // undefined

// Can get all variable names with variableNames;
console.log(varStore.variableNames); // ["a", "b"]

// Can get all stored objects with variables
console.log(varStore.variables); // [a: {value: "b", const: false}, b: {name: "b", const: false}]

Delete elements

// Can delete a variable with del
console.log(varStore.has("a")); // true
varStore.del("a");
console.log(varStore.has("a")); // false

Delete multiple elements at once

// Add variable back
varStore.set({name: "a", value: "b"});

// Delete multiple variables at once with del by passing in array
console.log(varStore.has("a")); // true
console.log(varStore.has("b")); // true
varStore.del(["a", "b"]);
console.log(varStore.has("a")); // false
console.log(varStore.has("b")); // false

Cannot set variable names to restricted values using set.

// Restricted names cannot be added using set, will throw error
try {
   varStore.set({name: "ans", value: "b"});
} catch(e) {
   console.log(e.message); // Cannot set variable to restricted name
}

Can set variable names to restricted values using setRestricted.

// Restricted names can be added using setRestricted
varStore.setRestricted({name: "ans", value: "b"});
console.log(varStore.get("ans")); // "b"

clear will clear all variables, including const

// Clear will empty all variables, including const
varStore.set({name: "a", value: "b"});
varStore.set({name: "b", value: "d"});
console.log(varStore.variableNames); // ["a", "b"]
varStore.clear();
console.log(varStore.variableNames); // []

clearNonConst will clear all variables except const

// clearNonConst will empty all variables, except const
varStore.set({name: "a", value: "b"});
varStore.set({name: "b", value: "d"});
varStore.set({name: "c", value: "c", const: true});
console.log(varStore.variableNames); // ["a", "b", "c"]
varStore.clearNonConst();
console.log(varStore.variableNames); // ["c"]

Cannot over write const values

// Variables declared as const cannot have their value change, will throw error
console.log(varStore.has("c")); // true

try {
   varStore.set({name: "c", value: "d"});
} catch(e) {
   console.log(e.message); // Cannot change const value
}

API

VariableStore

Constructor takes a valid regex and array of restricted variable names. Invalid regexs will throw an error on construction. If second parameter is not an array an error will throw.

Construction

const regex    = /^[a-zA-Z\_]\w*$/;
const restrictedNames = ["ans"];

const varStore1 = new VariableStore();
const varStore2 = new VariableStore(regex);
const varStore3 = new VariableStore(regex, restrictedNames);

Returns VariableStore object.

Computer Properties

variableNames

Returns an array of all variable names currently in store.

const regex    = /^[a-zA-Z\_]\w*$/;
const restrictedNames = ["ans"];
const varStore = new VariableStore(regex, restrictedNames);

// Insert variables
varStore.set({name: "a", value: 2});
varStore.set({name: "b", value: 3});

// Get all variable names
console.log(varStore.variableNames); // ["a", "b"]

variables

Returns an array of all variable names currently in store.

const regex    = /^[a-zA-Z\_]\w*$/;
const restrictedNames = ["ans"];
const varStore = new VariableStore(regex, restrictedNames);

// Insert variables
varStore.set({name: "a", value: 2});
varStore.set({name: "b", value: 3});

// Get all variable objects
console.log(varStore.variables); // [{a: {value: 2, const: false}}, {b: {value: 3, const: false}}]

Methods

set

Set adds a value to the variable store. Must be specific form, and not be a reserved word.

const regex    = /^[a-zA-Z\_]\w*$/;
const restrictedNames = ["ans"];
const varStore = new VariableStore(regex, restrictedNames);

// Variables must inserted as objects with {name (req), value (req), const (optional)}
const var1 = {name: "a", value: 1};
const var2 = {name: "b", value: 2, const: true};
varStore.set(var1);
varStore.set(var2);

// Attempt to set variable with object missing name and value
try {
   varStore.set({foo: 1, bar: 2});
} catch(e) {
   console.log(e.message); // insert object must have name and value
}

// Attempt to set variable with reserved name
try {
   varStore.set({name: "ans", value: 2});
} catch(e) {
   console.log(e.message); // Variable cannot be a reserved word: ans
}

// Attempt to overwrite a constant variable
try {
   varStore.set({name: "b", value: 3});
} catch(e) {
   console.log(e.message);
}

Will throw an error if the variable name doesn't match the regex or the name is a restricted value;

setRestricted

Allows for setting restrictedValues as variable names

// Restricted names can be set with setRestricted
varStore.setRestricted({name: "ans", value: "f"});
console.log(varStore.get("ans")); // f

Will throw an error if the variable name doesn't match the regex.

has

Returns boolen value of whether value is in variable store.

const regex    = /^[a-zA-Z\_]\w*$/;
const restrictedNames = ["ans"];
const varStore = new VariableStore(regex, restrictedNames);

// Insert a variable
varStore.set({name: "a", value: 2});

// See if the variable is in the store
console.log(varStore.has("a")); // true

// See if random variable is in the store
console.log(varStore.has("foo")); // false

get

Will retrieve the variable value from the store, or throw an error if it does not contain variable.

const regex    = /^[a-zA-Z\_]\w*$/;
const restrictedNames = ["ans"];
const varStore = new VariableStore(regex, restrictedNames);

// Insert a variable
varStore.set({name: "a", value: 2});

// Can get variable values using get
console.log(varStore.get("a"));

// Will throw error if you attempt to get a non existant value
try {
   varStore.get("b");
} catch(e) {
   console.log(e.message); // Variable does not exist
}

Throws error if an invalid variable is accessed.

del

Used to delete variables from VariableStore, either single name, or array of names.

const regex    = /^[a-zA-Z\_]\w*$/;
const restrictedNames = ["ans"];
const varStore = new VariableStore(regex, restrictedNames);

// Insert a variable
varStore.set({name: "a", value: 2});
console.log(varStore.has("a")); // true

// Delete variable using delete
varStore.del("a");
console.log(varStore.has("a"));

varStore.set({name: "a", value: 2});
varStore.set({name: "b", value: 3});
console.log(varStore.has("a")); // true
console.log(varStore.has("b")); // true

// Can delete multiple variables at a time by passing array
varStore.del(["a", "b"]);
console.log(varStore.has("a")); // false
console.log(varStore.has("b")); // false

// Deleting non-existant variables will do nothing
varStore.del("h");

clear

Used to clear variables, including constants.

const regex    = /^[a-zA-Z\_]\w*$/;
const restrictedNames = ["ans"];
const varStore = new VariableStore(regex, restrictedNames);

// Insert variables
varStore.set({name: "a", value: 2});
varStore.set({name: "b", value: 3});
console.log(varStore.has("a")); // true
console.log(varStore.has("b")); // true

// Clear will clear all variables including constant
varStore.clear();
console.log(varStore.has("a")); // false
console.log(varStore.has("b")); // false

clearNonConst

Used to clear variables except constants

const regex    = /^[a-zA-Z\_]\w*$/;
const restrictedNames = ["ans"];
const varStore = new VariableStore(regex, restrictedNames);

// Insert variables
varStore.set({name: "a", value: 2});
varStore.set({name: "b", value: 3});
varStore.set({name: "c", value: 4, const: true});
console.log(varStore.has("a")); // true
console.log(varStore.has("b")); // true

// Clear will clear all variables including constant
varStore.clearNonConst();

Scripts

Testing

To run mocha/chai tests. npm run test

Examples

To run the main example. npm run ex

License

VariableStore.js is released under the MIT license.