add some more types

.travis.yml

@@ -4,5 +4,4 @@ node_js:
 notifications:
   email: false
 script:
-  - npm run lint
   - npm test

lib/TreeSearch.ts

@@ -43,21 +43,27 @@ export function search(simplificationFunction, node, preOrder) {
 }
 
 class TreeSearchImpl {
-  // Returns a function that performs a preorder search on the tree for the given
-  // simplification function
+
+  /**
+   * Returns a function that performs a preorder search on the tree for the given
+   * simplification function
+   * */
   preOrder(simplificationFunction) {
     return function (node) {
       return search(simplificationFunction, node, true);
     };
   }
 
-  // Returns a function that performs a postorder search on the tree for the given
-  // simplification function
+  /**
+   * Returns a function that performs a postorder search on the tree for the given
+   * simplification function
+   * */
   postOrder(simplificationFunction) {
     return function (node) {
       return search(simplificationFunction, node, false);
     };
   }
+
 }
 
 export const TreeSearch = new TreeSearchImpl();

lib/factor/FactorString.ts

@@ -1,6 +1,6 @@
 import * as math from "mathjs";
 import { stepThrough } from "./stepThrough";
-import {emptyResponse} from '../util/empty-response';
+import { emptyResponse } from "../util/empty-response";
 
 export function factorString(expressionString, debug = false) {
   try {

lib/factor/stepThrough.ts

@@ -13,21 +13,19 @@ import { isQuadratic } from "../checks/isQuadratic";
  * */
 export function stepThrough(node, debug = false) {
   if (debug) {
-    // eslint-disable-next-line
     console.log("\n\nFactoring: " + printAscii(node, false));
   }
 
   if (hasUnsupportedNodes(node)) {
     return [];
   }
 
-  let nodeStatus;
   const steps = [];
 
   node = flattenOperands(node);
   node = removeUnnecessaryParens(node, true);
   if (isQuadratic(node)) {
-    nodeStatus = factorQuadratic(node);
+    const nodeStatus = factorQuadratic(node);
     if (nodeStatus.hasChanged()) {
       steps.push(nodeStatus);
     }

lib/node/NodeStatus.ts

@@ -1,5 +1,6 @@
 import { ChangeTypes } from "../ChangeTypes";
 import { NodeType } from "./NodeType";
+import {StepNode} from './StepNode';
 
 /**
  * This represents the current (sub)expression we're simplifying.
@@ -46,7 +47,7 @@ export class NodeStatus {
    * A wrapper around the Status constructor for the case where node hasn't
    * been changed.
    * */
-  static noChange(node) {
+  static noChange(node: StepNode) {
     return new NodeStatus(ChangeTypes.NO_CHANGE, null, node);
   }
 

lib/simplifyExpression/fractionsSearch/addConstantAndFraction.ts

@@ -5,13 +5,14 @@ import { evaluate } from "../../util/evaluate";
 import { NodeType } from "../../node/NodeType";
 import { NodeStatus } from "../../node/NodeStatus";
 import { NodeCreator } from "../../node/Creator";
+import {StepNode} from '../../node/StepNode';
 
 // Adds a constant to a fraction by:
 // - collapsing the fraction to decimal if the constant is not an integer
 //   e.g. 5.3 + 1/2 -> 5.3 + 0.2
 // - turning the constant into a fraction with the same denominator if it is
 //   an integer, e.g. 5 + 1/2 -> 10/2 + 1/2
-export function addConstantAndFraction(node) {
+export function addConstantAndFraction(node: StepNode): NodeStatus {
   if (!NodeType.isOperator(node) || node.op !== "+" || node.args.length !== 2) {
     return NodeStatus.noChange(node);
   }

lib/simplifyExpression/fractionsSearch/addConstantFractions.ts

@@ -6,6 +6,7 @@ import { evaluate } from "../../util/evaluate";
 import { NodeType } from "../../node/NodeType";
 import { NodeStatus } from "../../node/NodeStatus";
 import { NodeCreator } from "../../node/Creator";
+import {StepNode} from '../../node/StepNode';
 
 // Adds constant fractions -- can start from either step 1 or 2
 // 1A. Find the LCD if denominators are different and multiplies to make
@@ -15,7 +16,7 @@ import { NodeCreator } from "../../node/Creator";
 // 2A. Combines numerators, e.g. 4/6 + 4/6 ->  e.g. 2/5 + 4/5 --> (2+4)/5
 // 2B. Adds numerators together, e.g. (2+4)/5 -> 6/5
 // Returns a Status object with substeps
-export function addConstantFractions(node) {
+export function addConstantFractions(node: StepNode): NodeStatus {
   let newNode = node.cloneDeep();
 
   if (!NodeType.isOperator(node) || node.op !== "+") {

lib/simplifyExpression/fractionsSearch/cancelLikeTerms.ts

@@ -7,6 +7,7 @@ import { NodeStatus } from "../../node/NodeStatus";
 import { NodeCreator } from "../../node/Creator";
 import { printAscii } from "../../util/print";
 import { PolynomialTerm } from "../../node/PolynomialTerm";
+import {StepNode} from '../../node/StepNode';
 
 // Used for cancelTerms to return a (possibly updated) numerator and denominator
 class CancelOutStatus {
@@ -24,7 +25,7 @@ class CancelOutStatus {
 // Cancels like terms in a fraction node
 // e.g. (2x^2 * 5) / 2x^2 => 5 / 1
 // Returns a Status object
-export function cancelLikeTerms(node) {
+export function cancelLikeTerms(node: StepNode): NodeStatus {
   if (!NodeType.isOperator(node) || node.op !== "/") {
     return NodeStatus.noChange(node);
   }

lib/simplifyExpression/fractionsSearch/index.ts

@@ -18,8 +18,11 @@ import { simplifyPolynomialFraction } from "./simplifyPolynomialFraction";
 import { cancelLikeTerms } from "./cancelLikeTerms";
 import { simplifyFractionSigns } from "./simplifyFractionSigns";
 import { NodeStatus } from "../../node/NodeStatus";
+import {factorString} from '../../factor/FactorString';
+import {StepNode} from '../../node/StepNode';
+
+const SIMPLIFICATION_FUNCTIONS: ReadonlyArray<(node: StepNode) => NodeStatus> = [
 
-const SIMPLIFICATION_FUNCTIONS = [
   // e.g. 2/3 + 5/6
   addConstantFractions,
 

lib/simplifyExpression/fractionsSearch/simplifyFractionSigns.ts

@@ -3,20 +3,21 @@ import { Negative } from "../../Negative";
 import { NodeType } from "../../node/NodeType";
 import { NodeStatus } from "../../node/NodeStatus";
 import { NodeCreator } from "../../node/Creator";
+import {StepNode} from '../../node/StepNode';
 
 // Simplifies negative signs if possible
 // e.g. -1/-3 --> 1/3   4/-5 --> -4/5
 // Note that -4/5 doesn't need to be simplified.
 // Note that our goal is for the denominator to always be positive. If it
 // isn't, we can simplify signs.
 // Returns a Status object
-export function simplifyFractionSigns(fraction) {
-  if (!NodeType.isOperator(fraction) || fraction.op !== "/") {
-    return NodeStatus.noChange(fraction);
+export function simplifyFractionSigns(node: StepNode): NodeStatus {
+  if (!NodeType.isOperator(node) || node.op !== "/") {
+    return NodeStatus.noChange(node);
   }
-  const oldFraction = fraction.cloneDeep();
-  let numerator = fraction.args[0];
-  let denominator = fraction.args[1];
+  const oldFraction = node.cloneDeep();
+  let numerator = node.args[0];
+  let denominator = node.args[1];
   // The denominator should never be negative.
   if (Negative.isNegative(denominator)) {
     denominator = Negative.negate(denominator);
@@ -27,6 +28,6 @@ export function simplifyFractionSigns(fraction) {
     const newFraction = NodeCreator.operator("/", [numerator, denominator]);
     return NodeStatus.nodeChanged(changeType, oldFraction, newFraction);
   } else {
-    return NodeStatus.noChange(fraction);
+    return NodeStatus.noChange(node);
   }
 }

lib/simplifyExpression/fractionsSearch/simplifyPolynomialFraction.ts

@@ -3,13 +3,14 @@ import { PolynomialTerm } from "../../node/PolynomialTerm";
 import { NodeStatus } from "../../node/NodeStatus";
 import { NodeCreator } from "../../node/Creator";
 import { arithmeticSearch } from "../arithmeticSearch/ArithmeticSearch";
+import {StepNode} from '../../node/StepNode';
 
 // Simplifies a polynomial term with a fraction as its coefficients.
 // e.g. 2x/4 --> x/2    10x/5 --> 2x
 // Also simplified negative signs
 // e.g. -y/-3 --> y/3   4x/-5 --> -4x/5
 // returns the new simplified node in a Status object
-export function simplifyPolynomialFraction(node) {
+export function simplifyPolynomialFraction(node: StepNode): NodeStatus {
   if (!PolynomialTerm.isPolynomialTerm(node)) {
     return NodeStatus.noChange(node);
   }

lib/simplifyExpression/stepThrough.ts

@@ -14,7 +14,7 @@ import { arithmeticSearch } from "./arithmeticSearch/ArithmeticSearch";
 import { functionsSearch } from "./functionsSearch";
 import { fractionsSearch } from "./fractionsSearch";
 import { basicsSearch } from "./basicsSearch";
-import {emptyResponse} from '../util/empty-response';
+import { emptyResponse } from "../util/empty-response";
 
 // Given a mathjs expression node, steps through simplifying the expression.
 // Returns a list of details about each step.

lib/util/removeUnnecessaryParens.ts

@@ -3,6 +3,7 @@ import { PolynomialTerm } from "../node/PolynomialTerm";
 import { LikeTermCollector } from "../simplifyExpression/collectAndCombineSearch/LikeTermCollector";
 import { resolvesToConstant } from "../checks/resolvesToConstant";
 import { canSimplifyPolynomialTerms } from "../checks/canSimplifyPolynomialTerms";
+import {StepNode} from '../node/StepNode';
 
 // Removes any parenthesis around nodes that can't be resolved further.
 // Input must be a top level expression.
@@ -25,7 +26,7 @@ export function removeUnnecessaryParens(node, rootNode = false) {
 // it doesn't change the value of the expression. Returns a node.
 // NOTE: after this function is called, every parenthesis node in the
 // tree should always have an operator node or unary minus as its child.
-function removeUnnecessaryParensSearch(node) {
+function removeUnnecessaryParensSearch(node: StepNode): StepNode {
   if (NodeType.isOperator(node)) {
     return removeUnnecessaryParensInOperatorNode(node);
   } else if (NodeType.isFunction(node)) {

test/simplifyExpression/simplify.test.ts

@@ -24,7 +24,7 @@ describe("mixed cases", () => {
     // ["(a^2+2*a+1)/(a+1)", "a+1"] not working
   ];
   tests.forEach((t) => testSimplify(t[0], t[1]));
-})
+});
 
 describe("simplify (arithmetic)", () => {
   const tests = [

test/solveEquation/solveEquation.test.ts

@@ -19,11 +19,9 @@ function testSolve(equationString, outputStr, debug = false) {
 }
 
 describe("mixed cases", () => {
-  const tests = [
-    ["3(x+2)=12", "x = 2"]
-  ];
+  const tests = [["3(x+2)=12", "x = 2"]];
   tests.forEach((t) => testSolve(t[0], t[1]));
-})
+});
 
 describe("solveEquation for =", function () {
   const tests = [